WASHINGTON - Senators from Wyoming, Montana and North Dakota pressed the commander of the U.S. Strategic Command on Monday to maintain the region's 500 nuclear missiles, responding to recent reports that efforts may be afoot to reduce the fleet.

The Pentagon may try to reduce the number in a review of military strategy due out in early February. Montana Sens. Max Baucus and Conrad Burns, along with Wyoming Sen. Craig Thomas, told a news conference after their meeting with Gen. James E. Cartwright that they have heard reports that the military expects to recommend reducing the fleet by about 10 percent.

A Washington trade publication has fueled that rumor, posting what it said is a summary draft of the report, known as the Quadrennial Defense Review, on its Web site. According to Inside Washington Publishers' InsideDefense.com, the Pentagon report calls for reducing the fleet to 450.

Pentagon officials have been quiet on their plans but have not ruled out further decreasing the nuclear stockpile, which has been slowly reduced since the end of the Cold War.

The missiles are based at F.E. Warren Air Force Base at Cheyenne, Malmstrom Air Force Base at Great Falls, Mont., and Minot Air Force Base at Minot, N.D.

The senators said they argued to Cartwright that nuclear deterrence is still an important strategy, even in a changing military.

"We must not let our guard down and let our enemy know we have an empty holster, so to speak," said Burns, a Republican.

Thomas said discussions are ongoing.

"We continue to work with the Pentagon to ensure that land-based missiles are part of a modern national defense that focuses not only on protecting us from the dangers of non-affiliated terrorist enemies, but also rogue nation states now and into the foreseeable future," he said.

If the number is reduced, Burns said, it will probably take five to six years to remove the missiles.

Several missile-state senators inserted language into a defense bill last year that calls on the Pentagon to keep all the missiles, stating that it is national policy not to decrease the current number. But the Department of Defense can still make its own decision.