A US military helicopter crashed in Iraq on late Saturday, killing all 12 Americans aboard, the U.S. military said on Sunday.

The UH-60 Black Hawk helicopter crashed just before midnight Saturday near the restive City of Tal Afar in northwestern Iraq. All the killed are believed to be U.S. citizens, a U.S. spokesman said.

"Flight records indicate that eight passengers and four crew members were manifested for the flight. An immediate search and rescue operation was launched from nearby military installations," the spokesman said.

The cause of the crash was under investigation, the spokesman said, adding that there was bad weather at the time the helicopter crashed.

The Black Hawk was part of a two-aircraft team proving support for the 101st Airborne Division and was flying between bases in northern Iraq when communications were lost, the military said.

It was the second deadliest U.S. helicopter crash in Iraq since a transport helicopter crashed in bad weather in western Iraq on Jan. 26, 2005, killing 31 U.S. servicemen aboard.

Earlier, the U.S. military announced that three Marines "were killed by small-arms fire in separate attacks while conducting combat operation against the enemy" on Sunday near the western Iraqi town of Fallujah.

Another two Marines were killed by roadside bomb explosions to the south and east of Fallujah on Saturday, the military said.

With the latest casualties, at least 2,199 members of the U.S. military have died in Iraq since the March 2003 invasion.

Source: Xinhua