The US forces came under fierce attacks on Monday in restive areas west of Baghdad, local radio reported.
According to Sawa, a US-backed broadcasting station in Iraq, US military convoys were attacked by bombs and rocket-propelled grenades Monday morning in Fallujah, 50 km west of Baghdad, and Khaldiyah, 30 km further west.
Witnesses said heavy casualties were inflicted on the American forces in the attacks and subsequent firefighting, which lasted several hours.
But the US military in Baghdad did not confirm the incidents or any casualties.
The US forces are most frequently targeted in a vast land west and north of Baghdad, which is dubbed by some American officials as the "Sunni triangle".
As an anti-American sentiment simmered in the area, unidentified fighters launched around 20 attacks everyday in the past three months.
The US military blamed the attacks, which have killed over 80 US soldiers since May 1, on the loyalists of ousted Saddam Hussein's regime.
(Xinhua News Agency September 30, 2003)