WASHINGTON -- A battle for Iraq would pit 21st century weaponry against Cold War firepower.

The U.S. and British forces massed on Iraq's borders are armed with missiles and bombs guided with satellites and lasers, while Iraqi defenders rely on decades-old mortars, bazookas and machine guns -- and far less sophisticated missiles.

The biggest unknown in the aging Iraqi arsenal: chemical and biological weapons.

An invading coalition force would have more than enough firepower to overwhelm Saddam Hussein's deteriorating military, Pentagon officials and private analysts say.

Hundreds of warplanes are ready to rain satellite- and laser-guided bombs onto Iraqi targets, as well as perhaps as many as 1,000 Tomahawk cruise missiles and even some 21,000-pound behemoths that could wipe out hundreds of troops in one blast.

"I pity anyone who comes up against that kind of power," Air Force Maj. Gen. Franklin "Judd" Blaisdell said Wednesday.

The United States has more than 800 M1 Abrams tanks and scores of AH-64 Apache helicopters which can destroy Iraq's aging, Soviet-built tanks from beyond the horizon. Some 270,000 U.S. and British troops are in the region to face an Iraqi army that's fewer than 400,000 soldiers and widely reported to be demoralized, poorly trained and inadequately equipped.

"It's somewhere under 50 percent of what its capability was in 1991 during the Gulf War in terms of conventional capability," Defense Secretary Donald H. Rumsfeld said last month.

Iraq's only military advance since a U.S.-led coalition ejected Saddam's forces from Kuwait a dozen years ago has been in its chemical and biological weapons, Rumsfeld and other Bush administration officials say. Many analysts agree.

Higher risk of use

"There's a higher risk of Saddam using chemical or biological weapons. That's different from the last war," said Anthony Cordesman, an expert on Iraq's military at the Center for Strategic and International Studies.

That's one reason behind the massive military buildup around Iraq: convincing Saddam's military that their defeat is so certain that using chemical or biological weapons would not be an advantage. Through news conferences, leaflets, broadcasts and other psychological warfare, the Pentagon is sending Iraqi units the message that anyone involved in the use of weapons of mass destruction would be treated harshly, as a war criminal, after an American victory.

Pentagon officials say they plan a ferocious attack if President Bush orders a war: thousands of bombs and missiles hitting Iraq each day, coupled with a swift drive toward Baghdad by armored ground units protected by air power. It's a strategy designed to produce "shock and awe" in the enemy, military officers say, persuading them to give up.

"The ability to drop such a high concentration of precision weapons on such a large scale certainly will induce an effect the likes of which I don't think has ever been seen in modern warfare," said former Army officer Andrew Krepinevich, a military analyst at the Center for Strategic and Budgetary Assessments.

The advances also reduce the chance of civilian casualties, Pentagon officials say.

And Pentagon planners say the precision will help avoid civilian casualties, as well.

Much of the coalition firepower on the ground is aimed at Baghdad, where officials and analysts say Saddam and his Republican Guard may try to make a last stand with bloody, urban combat. Although the narrow streets and tall buildings of a city lessen some American battle advantages, U.S. military officials say they expect to prevail in a battle for Baghdad.

"The Third Mechanized Division would be driving into Baghdad with Abrams tanks against a Republican Guard armed with bazookas and machine guns," said military analyst John Pike of GlobalSecurity.org. "The difference is, the last Gulf War it was an army against an army. This time, it's an army against a secret police force."

Still, even a small force can create big problems for the U.S. military with tactics like using weapons of mass destruction or sabotaging crucial infrastructure -- a tactic Rumsfeld and other Pentagon officials have repeatedly accused Saddam of planning.

"You don't need large forces to sabotage dams. You don't need large forces to sabotage oil fields," Krepinevich said. "They can be remotely detonated, and it cost us about $10 billion to clean up the oil fields in Kuwait." ------

On the Net:

Center for Strategic and International Studies: http://www.csis.org

Center for Strategic and Budgetary Assessments: http://www.csbaonline.org

GlobalSecurity: http://www.globalsecurity.org

Developments in the Iraq crisis Wednesday:

Britain set out a list of conditions for Iraq's disarmament, hoping to break an impasse at the United Nations that has left Prime Minister Tony Blair vulnerable at home because of his support for the tough U.S. line. The conditions include a TV appearance by Saddam Hussein renouncing weapons of mass destruction.

President Bush spoke with Russian President Vladimir Putin, Blair and the leaders of Mexico, Chile and Pakistan, the White House said.

Spanish Foreign Minister Ana Palacio said the U.S.-backed resolution may be withdrawn because of France's threatened veto. A Foreign Ministry official later played down Palacio's remarks, saying she was talking hypothetically, and declined to say what kind of disarmament deadline Saddam might get if no resolution is voted on.

U.S. aircraft dropped 120,000 leaflets over several sites between Baghdad and the southern Iraqi city of Basra. The messages included a warning to the Iraqi military not to use chemical or biological weapons against U.S. or allied troops, according to U.S. Central Command.

Iraq displayed a pilotless aircraft that resembled a large model plane with wings apparently made of balsa wood. It said the drone was the one the U.S. claims was designed to deliver chemical and biological weapons.

Soldiers fired shots in the air and police clashed with protesters as they tried to enter the port in Iskenderun, Turkey, where U.S. forces are unloading equipment ahead of a possible war.