Military officials say the OH-58 Kiowa helicopter, which was armed, responded to assist Iraqi police who were under small arms fire from the ground, reports CBS News' Pete Gow in Baghdad.
Lt. Col. Barry Johnson, a U.S. military spokesman in Baghdad, said the causes of the crash were under investigation.
Meanwhile, hundreds of Iraqi police candidates left restive Anbar province Friday for training in the capital, including 200 men who survived a suicide bomb attack last week that killed 58 people.
In other developments:
In Ramadi, half of the 400 police candidates that left for Baghdad were from Qaim, a frontier Anbar town near the Syrian border that has been the scene of repeated fighting between U.S. forces and insurgents — including many foreign fighters infiltrating from neighboring Syria. Anbar is predominantly Sunni Arab and is the focal point of much of the insurgency in Iraq.
The other 200 candidates were from Ramadi, an insurgent hotbed where hundreds of police recruits were targeted near the Ramadi Glass and Ceramics Works.
"On Jan. 5 a suicide bomber attacked the recruitment center in Ramadi killing more than 30 applicants. Despite that attack, the recruits returned en masse today," Marine Capt. Jeffrey S. Pool said.
The men are part of an effort to return police to Anbar, including Ramadi and nearby Fallujah.
"There are approximately 1,200 Iraqi police officers patrolling the streets of Fallujah with 400 more attending the Baghdad Police Academy. This is the first large group of Iraqi Police candidates from Ramadi and the Western Euphrates River Valley to attend the Ministry of Interiors police training," Pool said in announcement from Ramadi.
U.S. soldiers from 2nd Brigade Combat Team assisted in providing security for the convoy to Baghdad, he addded.