(Recasts with missile strike in North Waziristan)
By Adil Khan
BANNU, Pakistan, Sept 24 (Reuters) - A suspected U.S. drone fired a missile at a house in a northwest Pakistan militant stronghold on Thursday killing three people, Pakistani security officials said.
The attack came hours after Pakistani Taliban killed 11 pro-government militiamen in an ambush.
The Pakistani military has made gains against Islamist militant fighters in recent months after Taliban advances raised fears for the nuclear-armed country's stability.
The suspected U.S. missile struck a house near a religious school run by Afghan Taliban commander Jalaluddin Haqqani in the North Waziristan region on the Afghan border, the intelligence agency officials said.
The identity of the dead was not known, they said.
Pakistani President Asif Ali Zardari is due to meet his country's main backers, including President Barack Obama, at a donors' meeting in New York on Thursday.
The United States, facing mounting problems in Afghanistan, wants to stop support for the Afghan Taliban coming from Pakistan. It has stepped up drone missile strikes in militant-controlled border lands despite Pakistani objections.
Pakistani stocks .KSE gained nearly 3 percent in healthy turnover on hopes the Friends of Pakistan meeting in New York would result in more of a promised $5.7 billion in aid materialising, dealers said.
Pakistani action in its northwest is vital for U.S. efforts to tackle an intensifying Taliban insurgency in Afghanistan.
General Stanley McChrystal, the commander of U.S and NATO forces in Afghanistan, said in an assessment leaked to the media this week the Afghan insurgency was supported from Pakistan and Afghanistan needed Pakistani action.
Earlier, militants attacked members of a pro-government militia on their way to the town of Bannu, 240 km (150 miles) southwest of Islamabad, killing seven, including three ethnic Pashtun tribal chiefs, residents and security officials said.
"The militants then fired on tribesmen who were collecting the bodies and killed another two, while two more were killed in clashes with militants later," said an intelligence agency official in the region, who declined to be identified.
The military has encouraged Pashtun tribes to form militias, known as lashkars, to fight the militants.
Residents said five militants were killed in clashes with security forces.
The government launched an offensive in the area, which borders North Waziristan, in June with the support of pro-government tribesmen.
In Swat, 120 km (80 miles) northwest of Islamabad, militants killed two members of a lashkar while eight militants were killed in a clash to the west of the former Taliban bastion of Swat, military officials said.
The army has largely cleared the former Taliban bastion in Swat and surrounding areas but soldiers face pockets of resistance. (For more Reuters coverage of Afghanistan and Pakistan, see: here) (Additional reporting by Junaid Khan; Writing by Augustine Anthony; Editing by Robert Birsel) (For a Reuters blog on Pakistan, see: blogs.reuters.com/pakistan/)