KABUL — Insurgents armed with rifles, rocket-propelled grenades and mortars tried to storm a combat outpost in eastern Afghanistan on Saturday, setting off a battle that killed 30 attackers and wounded five coalition soldiers, NATO said.

Assailants struck from all sides in the nighttime attack on the outpost in Paktika province's Bermal district, where nearly all NATO forces are from the U.S. military.

The military called in close air-support and aircraft dropped three bombs to help repel the insurgents. According to NATO, the five coalition service members who were wounded in the attack continued fighting.

"Insurgents attacked from all directions," NATO said in a statement. It provided no further details.

The attack took place in an area about 200 kilometres south of Kabul that borders the Pakistani region of North Waziristan. The area is controlled largely by the Haqqani network, a Pakistan-based Taliban faction closely tied to al-Qaida.

The border region has long been a refuge for Islamist extremists from around the world and has been the target of numerous drone strikes against the Taliban, al-Qaida and the forces of the Haqqani network. Jalaluddin and Sirajuddin Haqqani, a former anti-Soviet commander and his son, are now battling American forces in eastern Afghanistan.