Air raid sirens blared and about 1 million Iraqis carrying blankets and food streamed out of Baghdad early Friday in an evacuation drill to test the nation's readiness for war.

As Iraqis jammed roads out of the capital, tensions grew between Israel and the United States over a Persian Gulf-related issue at the United Nations.Israel's foreign minister said the United States showed weakness by supporting a U.N. Security Council resolution condemning Jerusalem.

Iraqi President Saddam Hussein has repeatedly tried to link the Palestinian problem with the gulf crisis. That has made it difficult for the United States to remain loyal to Israel without offending its Arab allies.

President Bush was to meet later Friday with John Major, Britain's new prime minister. In several television interviews today, Major said the question of war was "in Saddam Hussein's hands."

During the drill many Iraqis stayed home, residents said. Participants ran on foot to civil defense centers or sped out of town in cars. Hundreds of buses waiting at centers took Iraqis to shelters north, east and south of Baghdad.

Roads leading out of the capital were jammed with thousands of cars, trucks, buses and even carriages pulled by tractors. The drill began at 7 a.m. and ended five hours later.

Iraq has been preparing for war since the U.N. Security Council authorized force to remove Iraq from Kuwait if it does not leave the emirate by Jan. 15. Iraqi media carry instructions for building bomb shelters and courses in civil defense and first-aid.

U.S. officials have suggested Iraq's cities could be bombed heavily in the event of war. Gen. Michael Dugan, the air force chief of staff, was fired in September for revealing contingency plans that involved bombing Baghdad.

The evacuation drill Thursday was conducted for the half of Baghdad that lies on the east bank of the Tigris River, but only about 1 million of the 2 million residents participated, said residents, who spoke on condition of anonymity.

A second exercise Saturday will cover west Baghdad.

Basra, Iraq's second-largest city with a million people, was evacuated in a similar exercise Thursday.

Bush met with members of Congress on Thursday and told them he believed Saddam was underestimating U.S. power and intentions, several legislators said.

Saddam must be made aware that "if we get into an armed situation, he's going to get his ass kicked," Rep. Elton Gallegly, R-Calif., quoted Bush as saying. Bush's remark was confirmed by another person at the meeting.

A Pentagon spokesman said 10,000 more U.S. troops reached Saudi Arabia this week, bringing the American force to 280,000. The spokesman, Bob Hall, said U.S. intelligence sources put the Iraqi force in and around Kuwait at 510,000.

The U.N. Security Council resolution passed 15-0 Thursday. It urges Israel to halt deportation of Palestinians from the West Bank and Gaza and urges the United Nations to monitor the safety of Palestinians there.

U.S. backing for the resolution was seen as an effort to preserve the Arab coalition against Saddam. It was the third time in two months that Washington failed to exercise its veto powers to shield Israel.

Israeli Foreign Minister David Levy said Friday that the United States had succumbed to Arab pressure.

"There is a weakness among the Americans that is brought about by America's dependency on the anti-Saddam coalition," Levy told Israel army radio.

Iraqi Foreign Minister Tariq Aziz said the vote "highlighted the double standards applied by the United States."

In related developments:

- Suez Canal officials have begun careful checks of ships to guard against any attempt by Iraq to scuttle a vessel in the waterlinks the Mediterranean and the Red Sea. Many of the supply ships carrying troops and materiel to the Persian Gulf region have come through the canal.

- An Iraqi test-firing of three medium-range missiles on Dec. 2 reportedly took U.S. military officials by surprise. The first launch of the series was complete before American satellites and sensors noticed it, the Los Angeles Times reported, and Israeli and U.S. officials readied their air forces for attack.