Allied planes bombed two military air defense sites in the southern no-fly zone over Iraq Wednesday in the third round of strikes in a week, defense officials said.

The bombing brought to 52 the number of days this year that such strikes were reported by the United States and the United Kingdom coalition, whose mission is to patrol two zones set up to protect Iraqi minorities following the 1991 Gulf War.

Coalition aircraft used precision-guided weapons to target an air defense communications facility near Al Jarrah, 90 miles southeast of Baghdad, and an air defense operations center near Tallil, 160 miles southeast of Baghdad, said a statement from the U.S. Central Command.

The strikes were launched at about 5:10 p.m. Tuesday in Washington — early Wednesday morning in Iraq — after Iraqis fired anti-aircraft artillery and surface-to-air missiles at coalition aircraft doing patrols, the statement said.

It said damage assessment was incomplete.

Iraq considers the patrols a violation of its sovereignty and frequently shoots at the patrols run in the southern zone by the Central Command and in the northern no-fly zone by the U.S. European Command. In response, coalition pilots try to bomb Iraqi air defenses.

The hostilities have been going on for years but are being watched more closely since the Bush administration has vowed to oust President Saddam's Hussein's regime. The Pentagon has also changed its targeting in recent months, not necessarily hitting back at facilities from which the hostilities originate, but rather planning strikes that will do the most to cripple Iraq air defenses.

On Tuesday, aircraft targeted other elements of the air defense system after taking fire from sites northeast of Mosul, said a statement from the U.S. European Command, which does the patrol mission in the northern zone.

Also in the past week, coalition planes targeted facilities on Oct. 15 in the southern zone near Al Kut, about 100 miles southeast of the capital, Baghdad.

According to figures released by the commands, the latest strike made Wednesday the 40th day this year that there has been a coalition bombing in the southern zone set up to protect Shiite Muslims. There have been 12 days this year on which U.S.-U.K. planes struck in the northern zone, set up to protect the Kurdish population.