Afghan government forces killed 31 suspected Taliban militants near the eastern border with Pakistan, the defence ministry said Monday.

Insurgents attacked an Afghan army position near Angore Adda in Paktika province late Sunday, triggering a four-and-a-half hour clash with both sides using heavy weapons, said ministry spokesman Gen Mohammed Zaher Azimi.

He said the militants eventually fled, leaving behind 28 dead bodies of their fighters. Four Afghan army soldiers were injured, one seriously. "The fighting was intense," Azimi said adding, that the army captured a lot of ammunition from the militants, including anti-aircraft and artillery shells and rocket launchers.

Gen Shorgul, deputy corps commander for the Afghan army in three eastern provinces including Paktia, said the militants had come across the border from Pakistan and fled back afterwards. 

Pakistan vehemently denies that it allows Taliban fighters sanctuary on its soil. In recent days, its army has been fighting with militants in north Waziristan on the Pakistan side of the border.

In a separate clash Sunday, militants attacked a truck carrying supplies for the US-led coalition forces in Surobi district of eastern Paktia province, killing the truck driver, Azimi said.

In fighting that followed, three more militants were killed and two arrested. Two Afghan army officers were wounded, he said.