Insurgents destroyed an American tank north of Baghdad, killing two U.S. soldiers, and wounded seven Ukrainians in the first ambush against the multinational force patrolling central Iraq, officials said Wednesday. The attacks were part of a dramatic upsurge in recent days.

The United Nations (searchsaid late Wednesday that it was temporarily pulling its remaining staff out of Baghdad, continuing the exodus of international organizations from the Iraqi capital. The U.N. decision was announced two days after a deadly homicide car bombing (searchat the Baghdad headquarters of the Red Cross.

The international Red Cross (searchannounced earlier Wednesday it was reducing its international staff. The humanitarian group Medecins Sans Frontieres, or Doctors Without Borders, also announced it had pulled out workers.

"We have asked our staff in Baghdad to come out temporarily for consultations with a team from headquarters on the future of our operations, in particular security arrangements that we would need to take to operate in Iraq," U.N. spokeswoman Marie Okabe said.

The upsurge in violence was being caused by foreign fighters, the Iraqi Governing Council (searchsaid Wednesday. The council called on neighboring countries to crack down on infiltrators crossing into Iraq and provide Iraqi authorities with information about former regime figures who may be hiding on their soil, according to a statement carried by the Arabic language television station Al-Jazeera.

Iraqi Foreign Minister Hoshyar Zebari will raise the border issue during a meeting of regional foreign ministers in Damascus, Syria next week, Al-Jazeera said.

Meanwhile, Fox news showed footage Wednesday night of what it called examples of torture carried out by Saddam Hussein's henchmen, saying the graphic scenes illustrated the brutality of the regime before the start of the war.

In one clip, a man is seen being partially beheaded with a sword by someone identified by Fox as part of Saddam's Fedayeen. In another, the black-clad fighters severed the fingers of a soldier accused of desertion as a crowd of civilians looked on. In yet another, Iraqis are bound and thrown off a multi-story building.

Fox said that the tape, grainy and in poor quality, originally came from an Iraqi who provided it to U.S. troops. Fox said it had just been declassified by the U.S. government. The network did not say how it obtained the tape nor could it say exactly where or when in Iraq the tape was shot.

The latest attacks -- 233 over the last seven days according to the U.S. military -- have driven the combat death toll during the occupation above the number killed before President Bush declared an end to active combat on May 1.

Two American soldiers from the 4th Infantry Division were killed and one was wounded late Tuesday when their Abrams battle tank apparently hit a land mine near Balad, 45 miles north of Baghdad, division spokeswoman Maj. Josslyn Aberle said.

Their deaths brought to 117 the number of American soldiers killed by hostile fire since May 1. A total of 114 U.S. soldiers were killed between the start of the war March 20 and the end of April.

It was the first M1 Abrams battle tank destroyed since May 1, military officials said. Several of the 68-ton vehicles -- the mainstay of the Army's armored forces -- were disabled in combat before May 1.

The ambush of the Ukrainians occurred Tuesday night when two armored personnel carriers rolled over land mines near Suwayrah, about 40 miles southeast of Baghdad.

After the vehicles were disabled, gunmen opened fire on the disembarked soldiers, a spokesman for the multinational division at Camp Babylon said on condition of anonymity.

The spokesman said it was the first ambush against the Polish-led force that since September has been patrolling a belt of central Iraq south of the capital. About 1,650 Ukrainians are serving in the Polish-led force of some 9,500 peacekeepers.

Also Wednesday, a U.S. defense official said that a senior member of Saddam Hussein's ousted government, Izzat Ibrahim al-Douri, is suspected of helping coordinate the attacks on American forces with members of Ansar al-Islam, a group linked to Al Qaeda.

And on Thursday, American soldiers carried out pre-dawn raids in Saddam's hometown of Tirkit, detaining more than a dozen suspects, some believed to be involved in setting up a new terrorist cell, the U.S. military said.

In Geneva, the International Committee of the Red Cross said it would remain in Iraq, but would reduce the number of international staff -- now about 30 -- and increase security for those who stay. The agency has 600 Iraqi employees.

"The ICRC remains committed to helping the people of Iraq," said Pierre Kraehenbuehl, the agency's director of operations.

Secretary of State Colin Powell had urged the Red Cross and other nongovernment organizations to stay in Iraq because "if they are driven out, then the terrorists win."

Baghdad police commander Maj. Gen. Hassan al-Obeid on Wednesday announced measures to bolster security in the capital, including additional 24-hour checkpoints and special patrols around sensitive locations, according to coalition-run Iraqi television.

Elsewhere, three soldiers from the 101st Airborne Division were slightly wounded Wednesday when up to seven roadside bombs exploded near their convoy in the northern city of Mosul, the military said.

And in Ramadi, 60 miles west of Baghdad, witnesses said an explosive device intended for U.S. troops detonated Wednesday as a civilian car was passing by, seriously injuring the driver.

Col. William Darley, a U.S. military spokesman, said American forces are now suffering an average of 33 attacks a day. That marked a dramatic escalation over the average of 12 daily attacks reported in mid-July.

By late September, occupation authorities reported the average ranged from "the low teens to the mid-20s" over the previous two months. On Oct. 23, the U.S. military said attacks averaged 26 daily between Oct. 8 and Oct. 22.

The violence escalated this week starting with the rocket attack Sunday against the Al-Rasheed Hotel, which killed an American officer and wounded 18 other people.

The attacks, which coincided with the start of the Muslim holy month of Ramadan, cast doubt on assertions by the Bush administration that conditions in Iraq are steadily improving.