PARIS, OCT. 12 -- A French newsmagazine reported today that the Pentagon has prepared a battle plan to liberate Kuwait and defeat Iraq in a four-day blitz that would destroy Saddam Hussein's armed forces but probably cost as many as 20,000 American lives. The Pentagon denied the magazine's report.

The weekly L'Express, citing an outline of a plan supposedly code-named Operation Night Camel that it said was leaked by an anonymous adviser to Defense Secretary Richard B. Cheney, claimed the attack would begin on a moonless November night with a massive air assault by U.S. warplanes from Turkey, Saudi Arabia and the aircraft carrier Independence in the Persian Gulf.

"I never talk about contingency plans or speculate on future operations of any kind," Cheney said before a speech to the Business Council in Hot Springs, Va. But a senior Pentagon official, who asked not to be identified, denied the report, staff writer John Burgess reported from Hot Springs. "There is no such operation as Night Camel," the official said.

Senior French military officials said the L'Express story's emphasis on massive use of American air power in the early stages of battle was "not inaccurate." But they doubted that the death toll would be so high because the air assault was likely to be so effective that Western ground forces would find little resistance from Iraq's occupation army.

According to L'Express, the plan's first phase, lasting six hours, would aim to annihilate Iraq's air and missile bases and neutralize its radar systems before any counterattacks could be launched.

In the second phase, warplanes and missiles would target Iraq's key military and industrial sites, including nuclear facilities, chemical weapons storehouses, arms factories and command bunkers. Air attacks would also be used to break up Iraqi tank forces near the border with Saudi Arabia.

A third phase would seek to sever all communications and supply lines between Kuwait and Iraq. The magazine said U.S. Green Berets and Navy commandos would operate behind Iraqi lines while multinational ground forces launched an offensive with combat helicopters and M-1 tanks to bottle up the 170,000 Iraqi forces inside Kuwait.

The last stage of the battle plan would involve a much larger offensive of 45,000 American Marines, 50,000 soldiers from pan-Arab forces, plus British and French ground troops converging on Kuwait to complete its liberation.

The magazine said that while Pentagon planners were confident the operation could succeed within four days, it would probably cost the lives of 20,000 American soldiers and provoke desperate Iraqi forces into using chemical weapons and inflicting grave damage to Saudi oil fields.