After four hours of instruction from Judge Peter K. Leisure, the jury began deliberations late today in the U.S. Football League's $1.69 billion antitrust suit against the National Football League.

The six-member jury of New Yorkers, which includes five women and no self-professed football fans, heard 10 weeks of testimony from the two sides. The jury began deliberating at 4 p.m. today and adjourned 90 minutes later. Officials from the two leagues are expecting a verdict within a week.

Reading from a 155-page charge, Leisure told jurors that "antitrust laws were enacted to protect competition, not competitors. . . . An intent to monopolize alone is not sufficient for you to find that defendants NFL illegally monopolized the relevant market or submarket. Thoughts or ideas or proposals do not restrict competition. Only actual conduct restricts competition."

In its suit, the USFL alleges that the NFL illegally "tied up" the three television networks through pressure and coercion and conspired to keep USFL teams out of such markets as Oakland and New York, all in violation of the Sherman Antitrust Act.

In addition to damages, the USFL seeks to force the NFL off one network so that the USFL might negotiate a deal with that network. Since announcing it will move from a spring schedule to fall play, beginning this year, the USFL has been unable to secure a network contract.

In a pretrial opinion, Leisure wrote that "television is at the heart of this case." In his instruction today, Leisure told jurors they should infer "no anticompetitive intent or effect" from the mere existence of the NFL's contracts with all three networks. He also instructed jurors to consider whether the NFL "used any monopoly power" on the networks to keep them from showing USFL games.

Leisure instructed jurors that if they find that the NFL committed illegal acts "maliciously, wantonly, or oppressively" that subsequently inflicted harm against the USFL, "then you, the jury, may award an amount of punitive or exemplary damages as you shall find to be proper."

According to an NFL official, the NFL has spent "in excess of $5 million but less than $10 million" in legal fees on this trial. The USFL has spent "about $4 million" on its legal fees, according to a USFL official.

If the NFL lost a substantial decision in this case, it certainly would appeal, which could tie up any damages award for several years. If the USFL loses, Commissioner Harry Usher said "owners would decide" whether to appeal.

Leisure's instructions could be crucial in leading the jury toward a verdict. An NFL source close to the case said Leisure's instructions were "75-25" in favor of the NFL, but he expressed displeasure that Leisure summarized the USFL's case point-by-point.

A high-ranking USFL official, after hearing the instructions to jurors, said Leisure "is trying to make winning the case hard on us."

Special correspondent John Kennedy contributed to this report.