A US helicopter has been shot down northeast of Baghdad and two soldiers on board were killed, the military said.

The helicopter was one of two that came under attack by small arms fire near Baquba, 60km northeast of Baghdad, late on Thursday.The other landed safely.

A military announcement said the two Task Force Liberty helicopters received small arms fire at 10.50pm (1850 GMT) while conducting operations in support of coalition forces.

One, a two-seater OH-58 Kiowa, landed safely at a nearby base after sustaining damage and its passengers were unharmed, while the other crashed, killing two soldiers, the military said.

"Coalition forces responded to the scene and secured the site," the announcement said. "The incident is under investigation."

The Kiowa is an armed reconnaissance helicopter that entered service with the US Army in 1986.

Task Force Liberty, under the command of the 42nd Infantry Division, has its headquarters in Saddam Hussein's hometown near Tikrit.

PHOTO CAPTION

A road is closed off by razor wire as Iraqi soldiers and police secure the area leading to a US helicopter crash close to Baquba. (AFP)