BAGHDAD — A U.S. military CH-47 Chinook helicopter was forced into an emergency landing early Sunday south of Samarra, military officials said, resulting in only minor injuries for those aboard.

Few details were available on the incident, but a military press release said an engine problem was to blame. No information was given on what unit the helicopter belonged to, how many were aboard, and what the injuries were to those hurt.

The 42nd Infantry Division send a quick reaction force to secure the landing site and did not encounter any enemy fire. An investigation is being conducted.