The US military has confirmed that seven people were killed when transport helicopter came down near Baghdad.

"A marine CH-46 helicopter went down in Al-Anbar province this morning while conducting routine operations," a statement said, referring to the twin-rotor Sea Knight, the marine version of the Chinook.
 

Major-General William Caldwell, a US military spokesman, said it went down 30km northwest of Baghdad. He did not say whether mechanical failure or ground fire had brought it down.

An al-Qaeda-linked group, the Islamic State of Iraq, claimed its "air defence brigade" shot down the helicopter. 
 
 "We tell the enemies that these [operations] are proof that God is giving us victory," the group said in a statement posted on a website used by Sunni groups.

"Hundreds of people saw the aircraft, their voices rising in chants of Allahu akbar [God is greatest]," the statement said.

Earlier, witnesses said the helicopter had been shot down in a field in the Sheik Amir area northwest of Baghdad, sending smoke rising from the scene, in a Sunni-dominated area between the Taji air base 20km north of Baghdad and Garma, 30km to the west of the capital.
   

Rash of crashes

A CH-46 has two crew members and can carry up to 55 passengers. They are used widely to transport troops and cargo around Iraq.

The reports came five days after a US army helicopter crashed in a hail of gunfire north of Baghdad, police and witnesses said - the fourth helicopter lost in Iraq in a two-week span.

US command said two crew members were killed in that crash.

The US military said on Sunday it was adjusting its tactics in Iraq after four helicopters were shot down in recent weeks.

Those helicopters were shot down in four separate incidents in which 21 US servicemen and private security contractors were killed.

Photo caption

CH-46 helicopter