Baghdad:A US Marinehelicopter crashed in Iraq,killing all seven crew members and passengers in what was the fifth downing ofa UShelicopter is less than three weeks.

The CH-46 Sea Knight, which can carry up to 25 passengersand four crew, went down Wednesday in Iraq'sal-Anbar province, one of the country's most hostile regions to the USpresence.

The USmilitary in Baghdaddid not say whether the helicopter crashed accidentally or was attacked. An AlQaeda-linked group, which calls itself the Islamic State in Iraq, claimedon its website that it had shot down the Chinook.

Earlier, at least 10 gunmen were killed in armed clasheswith Iraqi military forces in Ramadi on Wednesday, state-run al-Iraqia TVreported, citing an Iraqi military source.

"A number of suspected terrorists were detained during theclashes in Ramadi, 110 km west of Baghdad,"the source added.

In another development, US-led coalition forces detained twosuspected terrorists believed to have ties to an Al Qaeda cell in Taji, northof Baghdad, the US military reported.

The forces also seized several weapons and materialscommonly used to make explosives.

Meanwhile, several hundred Sunnis, Shiites and Turkomansprotested Wednesday against the decision to "normalise" oil-rich Kirkuk, which wouldinvolve the return of displaced Kurds to the city.

An Iraqi Supreme Committee meeting Sunday in Baghdad had decided to relocate Arabs living in Kirkuk to their places of origin in central and southern Iraq, inaddition to providing them with financial compensation.

Kirkuk is the centre ofnorthern Iraq'soil industry. It is an ethnically mixed city where Kurds, Arabs, Turkomans andChristians have been living together for centuries.

The Kurdish parties are pushing to make Kirkukpart of the autonomous Kurdish region in northern Iraq.