US forces retrieved bodies and wreckage yesterday after at least 17 soldiers died when two Black Hawk helicopters crashed in the northern Iraqi city of Mosul.

The latest disaster for US forces, involving their single heaviest loss of life since the Iraq conflict began, occurred only hours after Washington set the country on a swifter passage to self-rule in a bid to calm Iraqi anger at occupation.

But Defense Secretary Donald Rumsfeld insisted that US forces would not begin leaving when a transitional government takes power in June under a plan unveiled on Saturday by Iraq?s US-appointed Governing Council.

A US military spokesman described as speculation reports by Iraqi witnesses and one US officer at the scene that a rocket-propelled grenade had brought down the helicopters.

?Two aircraft crashed in the vicinity at 6:30 p.m. last night,? Major Trey Cate, spokesman for the 101st Airborne Division, told reporters near the crash site in Mosul yesterday.

?They impacted the ground 250 meters (yards) from each other,? he said, adding that 17 soldiers had been killed and five wounded. Another soldier was ?possibly unaccounted for.?

Cate said a formal investigation was under way. ?We are moving bodies and debris from the scene now?, he added.

One Black Hawk slammed into the roof of a house in Mosul?s Bab Sinjar neighborhood. The second hit a school building. Somehow, neither appears to have inflicted civilian casualties in the crowded residential area near the city center.

A US officer at the scene soon after the crashes said a rocket-propelled grenade had hit the tail rotor of one Black Hawk. Witnesses said it then collided with the second.

?I was watching TV when I heard a large explosion,? said local man Mohammad Badran. ?I looked outside the window and saw two helicopters. One was flying low and was on fire. The other was higher up. The first one climbed and hit the higher one.?

Three US helicopters have been brought down in the past three weeks, killing a total of 22 soldiers. On Wednesday, a suicide attack killed 19 Italians in the deadliest assault on non-US forces in postwar Iraq.

The unrelenting violence is a key factor pushing Washington to install a provisional government before a new constitution is prepared and elections held, reversing a sequence previously laid out in US-sponsored U.N. Security Council resolutions.

No early US pullout

But Rumsfeld sought to dispel suggestions that US forces might start leaving once the provisional government is in place.

?There are no changes in the security situation?, he said in Japan. ?We are on the map we were on last week, last month. This has nothing to do with US troops in Iraq.?

He said security in Iraq was on a ?separate track? from the Governing Council?s timetable on the political transition.

Jalal Talabani, who currently holds the council?s rotating presidency, said a sovereign Iraqi government would be in place by the end of June 2004, formally ending the occupation.

The government would be selected by an assembly to be picked by May by caucuses in each of Iraq?s 18 provinces, and the US-led Coalition Provisional Authority would be dissolved.

A constitution would be written and democratic elections held by the end of 2005, Talabani said.

?The presence of the forces of the United States and other countries will be discussed by the transitional government?, Talabani said. ?If we need them to stay, we will ask them to stay. If we don?t, we will respectfully ask them to leave.?

President Bush, seeking re-election next year, has said US troops will stay until Iraq is stabilized. But more than seven months after US-led invasion forces ousted Saddam Hussein, the country is far from calm.

Before Saturday?s crash of the Black Hawks, 160 US soldiers had died in action in Iraq since Bush declared major combat over on May 1.

Cate said one of the Black Hawks had been taking soldiers back to a base. The other was carrying a quick reaction force that was possibly responding to a drive-by shooting near a bank in Mosul, in which a soldier was shot in the leg.

By Seb Walker