Islamabad: Pakistani forces are zeroing in on two major Taliban bases in South Waziristan region as their offensive pushes deeper into militant bastion on the Afghan border, the military said on Sunday.

Pakistani soldiers fire mortars towards Taliban militant positions at the Sherwangi Tor village in the South Waziristan.

The army launched a major assault in South Waziristan on Sept. 17 to seize control of the lawless land after a string of attacks by militants, including a stunning assault on the army headquarters that killed more than 150 people.

The offensive is a major test for the Pakistani government and the military to stem the rising tide of Islamist militancy and is being closely followed by the United States and other Western nations embroiled in Afghanistan's growing conflict.

The military says an "important phase" of its three-pronged offensive has begun as troops had reached the outskirts of Sararogha and Makeen, two main bases of the militants in treacherous mountainous terrain.

Makeen is described as "the nerve centre" of the militants while Sararogha, about 20 km (13 miles) southeast of Makeen, houses a strategic fort manned by a paramilitary force until it was captured by the Taliban last year after killing several soldiers and taking dozens hostage.

"Security forces have surrounded Makeen from three directions," the military said in a statement.

A Pakistani soldier fires a heavy machine gun on Taliban positions at the Sherwangi Tor village in South Waziristan. Around 30,000 troops are taking part in the offensive against an estimated 10-12,000 militants in the semi-autonomous and lawless tribal belt.

Jets, choppers pound Makeen

Security officials said military jets and helicopter gunships pounded militant positions in and around Makeen during the battle.