The director of communications for the Iraqi government in al-Qaim, Abdul-Khaliq al-Rawi, told Aljazeera that he confirmed two US helicopters were shot down in Qusaybah on Wednesday during fighting that has raged since Saturday.

A US military official later denied, through an electronic message sent to Aljazeera, that the helicopters had been shot down and branded the report a rumour.

Meanwhile, east of Qusaybah, a town about 320km northwest of Baghdad, Marine AH-1W Super Cobra helicopters fired at and killed three armed men seen digging holes in a road, allegedly to place explosives, according to US Captain Jeffrey Pool.

Civilians killed at checkpoint

In another incident, at least two civilians - a woman and a child - were killed late on Tuesday at a US checkpoint southeast of Obaidi, the border town which saw some of the fiercest fighting of the latest US offensive, the military said.

Pool said Marines fired at their vehicle after it ignored repeated warnings to stop.

The driver jumped out of the moving car and fled on foot, leaving the vehicle and its passengers to continue toward the checkpoint, Pool said in a statement.

He was apprehended and held for questioning. The Marines said they thought the vehicle was a car bomb, the statement said.