SEOUL, South Korea (AP) _ A U.S. Army doctor was in serious condition after being stabbed with a knife by a South Korean man on a busy Seoul street, the U.S. military and South Korean police said Monday.

The doctor, identified by South Korean police as Maj. Barry David, was stabbed in the chest during a brawl with a South Korean man on Sunday at Itaewon near the main U.S. military compound, both sides said.

The attacker, identified by South Korean police as Lee Yong-kyu, 36, was picking up two knives from a roadside garbage can when the American officer passed by, police said.

Lee told police he became angry after the American said something that insulted him.

``We don't know exactly what happened, but Lee's testimony indicates that he is not mentally stable,'' said Kim Joon-su, a lieutenant at Yongsan Police Station.

The U.S. military confirmed that the doctor was hospitalized with stab wounds but refused to disclose other details, including his name and hometown.

Violent crimes are rare in South Korea, especially against Americans. About 37,000 U.S. troops are stationed in South Korea.