BAGHDAD, Iraq – A U.S. soldier on patrol in northern Baghdad was killed by a single shot from a sniper, the military said Tuesday.

The gunman escaped from the area as the soldier collapsed on the ground. He was evacuated to a first aid station but died shortly afterward, said Maj. Sean Gibson, a U.S. military spokesman.

The identity of the soldier, from the 1st Armored Division, was withheld pending notification of relatives.

The shooting came on the second day of a major operation across central and northern Iraq to seek out illegal weapons stores and hunt for ringleaders of the anti-American resistance.

Gibson said the soldier was shot in the chest late Monday, even though he was protected by body armor. The others on the patrol did not see the gunman, and it was not clear if the soldiers returned fire, Gibson said.

About 50 American soldiers have died in Iraq since major combat was declared over on May 1.