Turkish warplanes bombed Kurdish rebel targets in northern Iraq on Saturday in the third confirmed cross-border offensive by Turkish forces in less than a week, a statement posted on the military's Web site said.

The military said the bombing lasted nearly a half-hour on Saturday afternoon, and was followed by shelling from inside Turkish borders. It did not say how deep into Iraqi territory the warplanes penetrated, or which areas were shelled.

It vowed to continue military operations on both sides of Turkish-Iraqi border "no matter how the conditions are," the statement said.

Turkish jet fighters on Dec. 16 launched the first confirmed air assault on Iraqi soil since the U.S.-led invasion, bombing bases in northern Iraq held by the separatist Kurdistan Workers' Party, or PKK.

The United States and Iraq both have urged Turkey to avoid a major operation in the region, fearing it could destabilize what has been the calmest area in Iraq.

Turkish forces periodically have shelled across the border, and sometimes have carried out "hot pursuits" — limited raids on the Iraqi side that sometimes last only a few hours.

In a Nov. 5 meeting with Turkish Prime Minister Recep Tayyip Erdogan, U.S. President George W. Bush declared the PKK a "common enemy," and promised to share intelligence on the group.