BAGHDAD, Iraq – U.S. and Iraqi troops aided by warplanes and unmanned drones fanned out in a Baghdad neighborhood on Tuesday in search of an American soldier believed to have been abducted Monday.

The troops shut off roads and bridges, erected checkpoints, searched cars and went from house to house in the Karada neighborhood of the capital, U.S. military officials said.

“It’s pretty intense,” said Lt. Col. Jonathan Withington, a military spokesman. “Forces throughout Baghdad are working on it.”

The soldier, an American of Iraqi descent who worked as a linguist on a reconstruction team, was last seen inside Baghdad’s heavily fortified Green Zone on Monday afternoon. Officials believe he left the protected compound to visit Iraqi relatives in the city during the Eid al-Fitr holiday.

During the visit, three cars reportedly pulled up to the house, according to a military statement. Kidnappers, wearing dark rags over their faces, handcuffed the unnamed soldier and forced him into one of the vehicles, according to the statement. The abductors reportedly later called a relative of the soldier at the house, using the soldier’s cell phone.

The U.S. military also announced on Tuesday the deaths of four more American troops. One soldier was killed by a roadside bomb in Baghdad on Tuesday, while two Marines and a sailor were killed in the western Anbar province the day before. Their deaths raised to at least 90 the number of American troops killed this month.