BRIGHT, Senior Circuit Judge.

I. INTRODUCTION

Curtis Jackson and Nina E. Donaldson appeal following their jury-rendered convictions on a one-count indictment charging them with conspiracy to possess with intent to distribute, and distribution of, cocaine and cocaine base, in violation of 21 U.S.C. § 841(a)(1), (b)(1)(A), 846. Jackson and Donaldson allege various trial errors. We affirm.

II. BACKGROUND

A federal grand jury indicted seven persons, including George Walters, Dorrel Ashley, Maria Simmons, Georgia Jackson, Adams Robbins, Sr., Curtis Jackson and Nina Donaldson, on March 25, 1992, for a single count of conspiracy to possess with intent to distribute and distribution of cocaine and cocaine base. We limit our discussion of the facts to Curtis Jackson's and Donaldson's involvement in the conspiracy.

Walters ran the organization, which trafficked in cocaine powder from New York chiefly to Junction City, Kansas. There, other conspiracy members cooked the powder into cocaine base (crack) for distribution.

Donaldson, Walter's live-in girlfriend and the mother of his two children, carried the cocaine beginning in late 1989 or early 1990 from New York through Kansas City International Airport and on to Manhattan (Kansas) Airport and Junction City. Donaldson also delivered cocaine once to South Carolina for Walters, where another conspiracy member, David McLean, sold the drugs.

Curtis Jackson met Walters in Junction City in 1989. From mid-1990 through July, 1991, Jackson bought cocaine from Walters to sell. At the time of his arrest, Jackson owed Walters approximately $17,000.00 for the cocaine.

Four of the defendants, Walters, Ashley, Simmons and Georgia Jackson, pled guilty and testified at the trial of the remaining three defendants. The government deported McLean. A jury subsequently found Curtis Jackson, Donaldson and Robbins, Sr., guilty as charged on November 11, 1992, after an eight-day trial. The district court sentenced Donaldson within the sentencing guideline range to sixty months (five years) imprisonment; Jackson received a sentence within the guideline range of one hundred and sixty-eight months (fourteen years).

III. DISCUSSION A. Nina Donaldson

Donaldson contends that the district court abused its discretion by unduly limiting her cross-examination of certain Government witnesses, specifically, Linda Mendez-Sanchez and Bernard Mollahan. Donaldson states that she was precluded from cross-examining Mendez-Sanchez "as to the silence of [telephone] records regarding point to point calls," and from cross-examining Mollahan "as to whether there was any documentary proof that the Appellant had knowledge of those telephone numbers. . . ." Br. of Appellant Donaldson, at 11.

Donaldson does not cite any specific instance where she was in fact precluded from cross-examining the witnesses. In any event, after being granted permission to voir dire Mendez-Sanchez, the district court properly sustained the Government's objections to Donaldson's questions that exceeded the scope of determining foundation. Further, once the court admitted the telephone records, defendant had an opportunity to cross-examine the witnesses. Donaldson's argument thus lacks merit.

Next, Donaldson argues for the first time that the district court improperly commented on the evidence in the presence of the jury, resulting in plain error. According to Donaldson, "the trial judge essentially took on the role of unimpartial referee in the disputes between the Appellant and the Government. The trial judge vouched for the recollection of the Government's counsel, who likesame vouched for the testimony of the government witnesses." Br. of Appellant Donaldson, at 13 (citations to trial transcript omitted).

The district court did not directly comment on the evidence but ruled on objections; these rulings sometimes resulted in confrontations between Donaldson's attorney and the court. See infra, at 399-401 n. 3. Further, some of the allegedly improper comments occurred out of the jury's presence. Accordingly, no plain error occurred.

Next, Donaldson contends that the district court abused its discretion based upon the manner in which it conducted the trial and the confrontations that occurred between the court, defense counsel and the Government's attorney. She contends that reversal is warranted, citing United States v. Singer, 710 F.2d 431, 437 (8th Cir. 1983) (en banc).

The Government argues that Donaldson's reliance on Singer is misplaced and that under United States v. Turner, 975 F.2d 490, 493 (8th Cir. 1992), cert. denied, ___ U.S. ___, 113 S.Ct. 1053, 122 L.Ed.2d 360 (1993), she was not prejudiced or deprived of a fair trial. According to the Government, "the `combative environment' here did not rise to a quality warranting any contempt citations as was the case in Turner." Br. of Appellee, at 24. Moreover, the district court, sensitive to the situation, gave the jury a "Cautionary Instruction" pertaining to the conduct of the court and the attorneys to prevent any potential threat to the fairness of the trial.

We have carefully scrutinized the trial transcript. From our review, we note the following: both the Assistant U.S. Attorney and Donaldson's counsel made nitpicking objections; many of Mr. Gibson's objections were general — leading, improper form of the question, relevancy — and were addressed to preliminary matters which in no way involved disputed facts or facts material to the disposition of the case; Mr. Gibson frequently made statements rather than asked questions, to which the district court repeatedly admonished counsel not to do, and Mr. Gibson's continuation of this procedure aroused the ire of the court; a similar form of cross-examination by the prosecutor, which Mr. Gibson, unlike the Government, did not object to at the time, did not evoke the same irritation from the bench.

In our view, Singer is inapposite. There, we addressed whether the district court had so far injected itself into the trial as to have deprived the defendants of a fair trial by giving the jury the impression that the court favored the prosecution. In a six-to-three decision, this court answered in the affirmative, based upon the district court's interventions which were designed

to clarify government testimony, to help government counsel, to indicate to government counsel when he should or should not make objections, to instruct government counsel on how to make his evidence more intelligible, to suggest to him when he should stop the examination of a witness, to indicate to him what he should write on a blackboard in order to illustrate a point to the jury, and the like. In addition, on numerous occasions the court took over the questioning of government witnesses in order to make sure that the somewhat complicated facts of this case were clearly explained.

Id., 710 F.2d at 436.

The trial here more closely approximates the circumstances presented in Turner, 975 F.2d at 493. The conduct in that case, however, resulted in a significantly more hostile trial environment, where the lawyer for one of the co-defendants received four contempt citations due to confrontations with the district judge. See id. Further, although the trial of Donaldson, Jackson and Robbins, Sr., lasted only eight days, Judge Stevens did not try the Government's case or improperly interject himself into the trial proceedings. While the district court may have used sharp language in rejecting some of attorney Gibson's objections, the court's rulings in most of the questioned instances fell within the court's discretion under the Federal Rules of Evidence. See United States v. Lueth, 807 F.2d 719, 729 (8th Cir. 1986). Further, the court's rulings on substance did not amount to plain error.

We also note that a majority of the disputes between counsel and the court occurred outside of the jury's hearing. Moreover, the judge specially instructed the jury during the course of the trial, after the tenor of the interactions apparently had escalated, that his comments and any disputes between counsel and the court did not reflect on the guilt or innocence of the parties and could not be so considered by the jury. See ante, at 400-401 n. 4. We cannot say on this record that Donaldson was deprived of a fair trial. United States v. Scott, 26 F.3d 1458, 1465 (8th Cir. 1994). Accordingly, Donaldson's claim must fail.

Lastly, Donaldson argues that the district court abused its discretion upon allowing the Government to introduce into evidence testimony about her brother, Fidel Donaldson. She characterizes the evidence as irrelevant, inflammatory and an attack on her character. According to Donaldson, because her brother allegedly dealt drugs, testimony associating her with Fidel allowed the jury to convict her based solely on their association.

Donaldson fails to demonstrate how the testimony pertaining to her brother's association with the conspiracy and drug dealing was either irrelevant or that its prejudicial effect outweighed its probative value. The testimony elicited by the Government was in fact relevant to Donaldson's involvement in the conspiracy as a drug courier, and did not rise to the level of unfair prejudice.

B. Curtis Jackson

Jackson contends that the district court committed prejudicial error by failing to timely instruct the jury, based on his several requests, that it could only consider evidence that arose during the existence of the alleged conspiracy. Due to the lack of timely instruction, Jackson argues that "[i]t is clearly a distinct possibility that the jury established Appellant Jackson's membership in the alleged conspiracy based upon the testimony of pre or post-conspiracy activity." Br. of Appellant Jackson, at 13.

Pertinent to the issue, the district court gave the following limiting instruction to the jury at the end of the trial, which almost verbatim tracks the language of Eighth Circuit Instruction 5.06I (West 1989):

THE COURT: This is No. 18.

If you have found beyond a reasonable doubt that a conspiracy existed and that the defendant was one of its members, then you may consider acts knowingly done and statements knowingly made by defendant's co-conspirators during the existence of the conspiracy and in furtherance of it as evidence pertaining to the defendant, even though they were done or made in the absence of and without the knowledge of the defendant whose guilt or innocence you are then considering. This includes acts done or statements made before the defendant had joined the conspiracy for a person who knowingly, voluntarily and intentionally joined an existing conspiracy is responsible for all of the conduct of the co-conspirators from the beginning of the conspiracy.

Acts and statements which are made before the conspiracy began or after it ended are admissible only against the person making them and should not be considered by you against any other defendant.

Instruction No. 18, Br. of Appellee, Add. at 3 (emphasis added).

The district court's decision when to give a limiting instruction requires an exercise of discretion that we will not disturb absent an abuse of that discretion. Cf. United States v. Graham, 548 F.2d 1302, 1310 n. 4 (8th Cir. 1977) (reserving a decision whether, and if so, under what circumstances failure to give a requested limiting instruction at the time an extrajudicial statement of an alleged co-conspirator is offered into evidence constitutes reversible error). Jackson fails to direct the court's attention to any testimony that the jury could have improperly used to establish his participation in the conspiracy. In light of the above considerations, we reject Jackson's claim.

Jackson also argues that the confrontations between co-defendant Donaldson's attorney, the Assistant U.S. Attorney and the district court deprived him of his right to a fair trial, and that the district court improperly assisted the Government in questioning witnesses. Jackson had sought a severance both at pretrial and during the trial, which he now contends the district court erroneously denied. Jackson sets out numerous examples of the "magnitude of the problem," accompanied by citations to numerous additional instances. Br. of Appellant Jackson, at 16-22. This conduct, Jackson argues, "`place[d] the defense at a disadvantage in the eyes of the jury by casting the prosecutor in the rule [sic] of underdog . . . and suggest to the jury that he favored the government's position.'" Br. of Appellant Jackson, at 20 (quoting Singer, 710 F.2d at 436).

We conclude from our review of the excerpts set out by Jackson (relating to the confrontations and the district court's purported assistance to the Government) and of the entire transcript, that, as discussed previously, ante, at 402, no plain error exists prejudicial to Jackson. Moreover, as we have already noted, the district court in this case gave the jury a "Cautionary Instruction" pertaining to the conduct of the court and the attorneys. See ante, at 400-401 n. 4. Consequently, we conclude that the district court did not abuse its discretion by denying Jackson's motion to sever.

IV. CONCLUSION

Based upon the foregoing discussion, we affirm both defendants' convictions.