A U.S. Black Hawk helicopter crashed Friday near Saddam Hussein's hometown of Tikrit. The cause of the crash is under investigation. Tikrit is about 160 kilometers north of Baghdad. A large plume of smoke could be seen rising from the helicopter that crashed near a riverbank.

The Black Hawk is the U.S. Army's frontline helicopter designed to carry 11 combat troops. It is also used as a general transportation aircraft and for medical evacuations.

On October 25, anti-coalition forces attacked a Black Hawk helicopter with a rocket-propelled grenade. That incident also occurred in Tikrit. The helicopter was forced to land and all five crewmembers escaped as the aircraft became engulfed in flames.

Last Sunday, a U.S. Army Chinook helicopter was downed by what was believed to be a shoulder-fired missile near the town of Fallujah west of Baghdad. Sixteen U.S. soldiers were killed in what was the single worst incident against U.S. forces in Iraq.

The U.S. military has said there may be hundreds of shoulder-fired surface to air missiles in Iraq that continue to present a considerable threat to U.S. aircraft in the country.

Also in northern Iraq Friday, one U.S. soldier was killed and at least six others were wounded when their convoy came under attack in Mosul.

The U.S. military says the convoy, with the 101st Airborne Division, was attacked by a group of assailants firing rocket-propelled grenades.