NBC Universal and producer Dick Wolf struck a last-minute deal Sunday to keep "Law & Order" and its two spinoffs on the air, although "Law & Order: Criminal Intent" episodes will first be seen on the USA cable network.

The deal ensures an 18th season of "Law & Order" on NBC. That's second only to "Gunsmoke," which aired from 1955 to 1975 and was the longest-running network drama series on TV.

NBC announces its fall television schedule on Monday, opening a week where all the broadcasters outline next season's plans to advertisers in New York.

NBC had essentially concluded it had room for only two of Wolf's series on next year's schedule. "Law & Order: SVU" has the highest ratings of the three, so that was safe. After some brief conversations about shifting "Law & Order" to Time Warner Inc.'s TNT, the decision was made to keep "Criminal Intent" for USA, said Jeff Zucker, chairman of NBC Universal.

NBC and USA are corporate cousins within NBC Universal, and "Law & Order: Criminal Intent" reruns make up some of its most popular programming. Now USA will be able to premiere a full season's worth of 22 episodes of what had been an established network series, a first for the business. The series is entering its seventh season.

"This was a strategic decision by us," Zucker said. "We are really taking USA to a new stratosphere."

It's not clear when "Criminal Intent" episodes will air on NBC; they will likely be used to fill a hole when a new fall drama fails.

"Law & Order" sank sharply in the ratings this year, although that was partly expected with a move to Fridays, one of the least-watched nights on television. While it will be back for an 18th season, NBC executives declined Sunday to say whether it will start in the fall or midseason.

The deal also forces Wolf to cut production costs for the series and hit new financial targets, although they weren't publicly outlined. Wolf said this wouldn't result in any significant cast changes or be visible to viewers.

"Nobody was casting aspersions on the creative process," he said. "It was just costing too much for the realities of how the business has evolved."

NBC has suffered in the ratings this season, particularly this spring, with only "Heroes" emerging as a new hit. At the same time, USA is a very profitable operation.

NBC said the status of Fred Thompson, who plays District Attorney Arthur Branch on "Law & Order" and is considered a potential GOP presidential candidate, had nothing to do with the discussions. Thompson is under option for another season of ripped-from-the-headlines crime drama, but Wolf said Sunday he knew nothing of the actor-politician's plans.

"I haven't talked to him for the last two weeks," he said. "So your guess is as good as mine."

Keeping "Law & Order" on the air long enough to eclipse the "Gunsmoke" record is his "ultimate dream," Wolf said.

"Creatively, the show is still firing on all cylinders and I have no doubt the show's quality can and will continue for years to come," he said.