Updated

Two U.S. soldiers were killed and four wounded in separate attacks Wednesday in the northern city of Mosul (search), the military said. American troops in another northern city arrested five Iraqi policemen and 24 others suspected of ties to insurgents.

Guerrillas also struck at an Air Force C-17 (search) transport plane with a ground-fired missile, forcing it to return to Baghdad, a senior Pentagon official said.

The U.S. military in Baghdad said the plane reported an engine explosion on takeoff Tuesday; one of the 16 people aboard was slightly injured. The plane is from a unit based at McChord Air Force Base near Tacoma, Wash, a spokesman at the base said.

Meanwhile, Iraq's U.S.-appointed interim government established a war crimes tribunal to try former members of Saddam Hussein's regime.

Also in Mosul, residents said U.S. troops shot and killed a senior officer of the paramilitary group Saddam Fedayeen after storming his house Wednesday. The U.S. Army confirmed there were raids but declined comment on the reported death of Col. Ghanem Abdul-Ghani Sultan al-Zeidi.

The new tribunal will cover crimes committed from July 17, 1968 -- the day Saddam's Baath Party came to power -- until May 1, 2003 -- the day President Bush declared major hostilities over, said Abdel-Aziz al-Hakim, president of Iraq's Governing Council.

"Today is an important historic event in the history of Iraq," al-Hakim said.

The Associated Press first reported Friday that Iraq would create a war crimes tribunal.

The tribunal will try cases stemming from mass executions of Iraqi Kurds in the 1980s, as well as the suppression of uprisings by Kurds and Shiite Muslims after the 1991 Gulf War.

Al-Hakim said it would also try cases committed against Iran -- with which Iraq fought a bloody 1980-88 war -- and against Kuwait, which Iraq invaded in 1990, sparking the Gulf War.

U.S. authorities are holding several dozen of Saddam's top aides who could be tried by the new tribunal. These include Ali Hassan al-Majid -- known as "Chemical Ali" -- who gained notoriety for his savage campaign against Kurds.

Noor al-Din, a former appeals court judge, said the tribunal could try Saddam, who has eluded capture, in absentia.

In Mosul, one soldier from the U.S. Army's 101st Airborne Division died and another was wounded when gunmen fired on troops guarding a gasoline station. U.S. soldiers killed one assailant, a military spokesman said.

But witnesses said the attackers escaped and U.S. troops opened fire on passing cars, killing a driver. Residents identified the dead passenger as a member of the Patriotic Union of Kurdistan, a major pro-American political party. The PUK's Mosul headquarters is across the street from the gas station.

A few hours later, guerrillas detonated a roadside bomb and opened fire on a U.S. military convoy in the city, killing another U.S. soldier and wounding three others, the spokesman said.

The deaths brought to 450 the number of American troops who have died in Iraq since the U.S.-led invasion on March 20. Of those, 310 have died as a result of hostile action. The British military has reported 52 deaths; Italy, 17; Spain, eight, and Denmark, Ukraine and Poland one each.

There has been a surge of attacks in Mosul, which was largely quiet in the months following the invasion. The predominantly Sunni Muslim city is home to many former soldiers and party loyalists of Saddam, but sits outside the so-called Sunni Triangle north and west of Baghdad, where the majority of attacks on American forces have occurred since Saddam's ouster. U.S. troops killed Saddam's sons, Odai and Qusai, in Mosul in July.

Pentagon officials said in Washington that 250 of the 700 Iraqi soldiers trained by the U.S.-led occupation authority have quit. The battalion completed a nine-week basic training course in October and was to be the core of a new Iraqi army.

It was uncertain exactly why a third abandoned their new jobs, though some had complained that the starting salary -- $60 a month for privates -- was too low, officials said.

In Madrid, Spanish Prime Minister Jose Maria Aznar announced the arrests of suspects in the slaying of seven Spanish intelligence agents in an ambush south of Baghdad on Nov. 29. The U.S. Army's 82nd Airborne Division said in a statement that 41 "enemy personnel," including the leader of the cell that carried out the attack, were detained.

In the oil-rich city of Kirkuk, U.S. troops and Iraqi police arrested 29 people, including five policemen, who were suspected of ties to Saddam, said Adnan Mohammed Saleh, a city police officer. Saleh said the policemen were suspected of passing intelligence to anti-occupation guerrillas.

Some coalition officials have recently warned the new U.S.-sponsored Iraqi security forces are being infiltrated by Saddam loyalists who are providing the guerrillas with information on occupation troops.

In northern Iraq, an Apache helicopter made an emergency landing 13 miles south of Mosul on Wednesday. A military spokesman said a technical problem caused a fire in the engine and the crew was safe.