BAGHDAD, July 10 (Xinhua) -- Multiple rounds of mortars or rockets were launched at the heavily-fortified Green Zone in central Baghdad on Tuesday, killing three people and wounding some 18 others, the U.S. Embassy said in a statement.

The three dead included a U.S. military service member, an Iraqi citizen and a third-country national of unknown nationality, according to the statement.

Some 18 persons were injured, among them two U.S. service members and three U.S. contract employees, it said.

A Xinhua correspondent in central Baghdad heard about 20 explosions in the Green Zone at about 4:15 p.m.(1315 GMT).

The Green Zone, which houses the U.S. Embassy, the Iraqi government offices and the Iraqi parliament, is often shelled by mortars rounds and rockets.