DANVILLE, Ky. -- Republican Dick Cheney and Democrat Joseph Lieberman Thursday differed -- at least in tone -- on how to tackle U.S. foes in Iraq and Yugoslavia in a vice presidential debate focusing significantly on foreign policy.

Cheney urged that Washington use the crisis in Yugoslavia to "test" Russian President Vladimir Putin's commitment to democracy and said Republican presidential candidate George W. Bush should get credit for proposing last week a Russian role in ending the turmoil.

Responding to a question about the stalemate with Iraqi President Saddam Hussein, Cheney -- who was defense secretary during the 1991 Gulf War that ousted Iraq from Kuwait -- said a Bush administration might "have to take military action to forcibly remove Saddam from power."

On Yugoslavia, Lieberman made no mention of Russia and said that if strongman leader Slobodan Milosevic has not yet been ousted from power, then the United States should continue to support a popular uprising by the Serbian people.

He said the United States should be proud of the role it played in recent years in stopping Milosevic's aggression and genocide in the Balkans.

Appearing at the only debate between the vice presidential candidates ahead of the November 7 election, the two men spoke hours after the Yugoslav opposition took charge of Belgrade's streets after a popular and almost bloodless revolution appeared to have swept Milosevic from power.

But there was uncertainty about Milosevic's whereabouts.

Serb opposition sources reported that he was in a bunker in eastern Serbia, protected by army troops, and could be mounting a coup.

U.S. officials were monitoring the situation closely, and did not rule out the possibility of a "last stand." President Clinton said military intervention was not appropriate.

Lieberman, a U.S. senator from Connecticut, said it appeared there would be "a very happy ending to a terrible story" of Milosevic's aggression in the Balkans.

If Milosevic has not yet been ousted, however, then Washington and its allies "should do everything we can to encourage the people of Serbia to do exactly what they have been doing over the last few days, to rise up and end this reign of terror by Milosevic and bring themselves back into the family of nations where they will be welcomed by the United States and others," Lieberman said.

He criticized Republicans for accusing the Democratic administration of Clinton and Vice President Gore of "overreaching" by using military force in the Balkans and said the Democrats were proven right.

AGGRESSION STOPPED

"We stopped the aggression and the genocide and therefore strengthened our relationships with our European allies and NATO and in fact, this made us more respected and trusted by our allies and more feared by our enemies," he said.

He credited Gore with a critical role in the policy.

Cheney said Bush supported the administration's approach to the Yugoslav province of Kosovo and would "do everything we can to support Mr. Milosevic's departure." He also ruled out U.S. military force.

He criticized Gore for "poo pooing" Bush's suggestion at last week's presidential debate that Russia be enlisted to use its influence to encourage Milosevic to cede power peacefully.

Now that the Yugoslav people have taken to the streets to insist that Milosevic accept the election of opposition candidate Vojislav Kostunica as president, "it is time to find out if (Putin) is committed to democracy" there, Cheney said.

Russia has strong religious and cultural ties with Serbia but Putin so far has not accepted Kostunica's election.

On Iraq, Cheney said the United States should seriously consider a military attack on Iraq if there was evidence that it was developing weapons of mass destruction.

He noted the coalition which defeated Iraq in 1991 was weaker today, with Arab states reopening diplomatic ties with Baghdad and U.N. inspectors no longer in Iraq to monitor its arms program.

"If in fact Saddam Hussein were taking steps to try to rebuild nuclear capability or weapons of mass destruction you'd have to give very serious consideration to military action to stop that activity," said Cheney.

"I don't think you can afford to have a man like Saddam Hussein with nuclear weapons in the Middle East," he added.

Lieberman said the decision to deploy military force against Iraq was too weighty to discuss in the heat of a political campaign and should be left to the commanders of the U.S. military and the nation's leaders.

But he said: "The fact is we will not enjoy real stability in the Middle East until Saddam Hussein is gone."