"Two US marines were killed in action and four US marines were wounded in action today," a US military spokesman said in a short statement released late on Thursday.

The spokesman provided no further details on the cause of death or where the incident took place.

US troops have been massing in Fallujah and Ramadi in recent weeks amid mounting expectations of a double-pronged assault on the Sunni Muslim bastions, west of Baghdad, believed to be the nerve centre of rebel activity.

The US-backed government of Prime Minister Iyad Allawi has pledged to crush pockets of resistance ahead of national elections promised by January.

On Thursday, a marine operation in Ramadi, the capital city of al-Anbar province, discovered and disarmed a youth centre that had been rigged with explosives along with more that two tons of explosives hidden in a mosque, the military said in a separate statement.

"The discoveries were made during a sweep of the city looking for improvised explosive devices," it said.

Fifty suspected insurgents were also netted in the sweep, it added.

The latest deaths brought to 1,120 the number of US military personnel killed in Iraq since the US-led invasion in March 2003, according to a Pentagon tally.

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