U.N. helicopter gunships fired rockets and machine guns Thursday at militiamen who attacked them as they patrolled the skies over eastern Congo's troubled Ituri province, the United Nations said.

Two U.N. helicopters were conducting a reconnaissance mission near the village of Kagaba when ground-based militiamen opened fire, said a spokesman for the U.N. peacekeeping mission, Madnoge Mounoubay.

Kagaba is about 30 miles southeast of the regional capital, Bunia.

No peacekeepers were wounded and the helicopters landed safely, though bullets struck one of the choppers during the clash, Mounoubay said by telephone from Bunia.

It was not clear who the militia group was, but peacekeepers believe the militiamen belonged to a local group called Ituri Patriotic Resistance Front, Mounoubay said.

The violence in Ituri came three days after a similar assault Monday against U.N. helicopters in a nearby village. Kinshasa-based U.N. spokesman Lt. Col. Jean-Paul Dietrich blamed Monday's attack on the Ituri Patriotic Resistance Front. He said the U.N. helicopters, which had been deployed to check reports of fighting between Congo's army and militiamen, replied with two rockets.

Most of the violence in eastern Congo over the last year has taken place further south in North Kivu province, where fighters loyal to warlord Laurent Nkunda skirmish regularly with militia groups and the army.

Congo's government has tried unsuccessfully for years to bring an end to violence in the east, a vast area of rural hills and forests. The 18,000-strong U.N. force has also failed to halt the fighting.