ANKARA, Turkey (AP) _ U.S. warplanes bombed an Iraqi air defense system in response to artillery fire Thursday as they patrolled a no-fly zone over northern Iraq, the U.S. military said.

The U.S. planes hit a site near Bashiqah, about 250 miles north of Baghdad, the Germany-based U.S. European Command said in a statement. All of the planes, based at Incirlik air base in southern Turkey, left the area safely, the statement said.

The incident was the eighth confrontation between U.S. jets and Iraqi forces in northern Iraq this year.

U.S. and British planes have frequently targeted Iraqi military sites since Iraq began challenging the patrols in December 1998. Baghdad does not recognize the no-fly zones, which were set up shortly after the 1991 Gulf War to protect Shiite Muslims in the south and Kurds in the north from the forces of Iraqi President Saddam Hussein.