One of two pilots whose Marine Corps fighter jets were reported missing in Iraq has been found, and investigators have concluded that their planes likely collided in the air, a senior defense official said Tuesday.

U.S. officials in Baghdad said the search was continuing.

At the Pentagon, an official with access to details of the search said an emergency beacon from one of the F/A-18 jets (search) was detected on the ground about 15 miles southwest of Karbala (search), in south-central Iraq.

The official discussed some details on condition of anonymity because the search is not finished.

An ejection seat from one of the jets was found at the site of the emergency beacon, but the official said he was not certain where the body was found.

There was one pilot in each of the single-seat jets, which had launched from the USS John Stennis on Monday. They were reported missing by U.S. military authorities on Monday evening.

The U.S. military said there was no indication of hostile fire in the area when contact was lost with the two warplanes.

The two F/A-18s were flying in support of coalition operations in Iraq, the military said.