KALAYA, Pakistan - Pakistani forces backed by tanks and artillery repulsed Taliban attacks in northwestern Orakzai on Sunday, killing nearly 40 militants, a government official said. Orakzai, southwest of Peshawar, has become a Taliban hub since security forces mounted offensives against their strongholds in other parts of the ethnic Pashtun northwest over the past year, security officials say. Pakistan, an important US ally has recently stepped up assaults in Orakzai and the militants have been retaliating. Sajid Khan, a government official in the region, told Reuters that several dozen militants attacked a security post in a village early on Sunday. "They used rocket-propelled grenades, mortars and machine guns, but our soldiers' response was quick and tough," said Khan, who is based in Kalaya, the region's main town. Twenty-five militants were killed and 10 wounded in the clash, he said. Hours later, militants ambushed a military convoy in a nearby village and at least a dozen militants were killed, Khan said. He said only one government soldier was wounded in the clashes. There was no independent confirmation of Khan's casualty tolls but a security official, who declined to be identified, gave similar figures in the clashes. Pakistan's action against militants over the past year has won US praise and eased fears that the militants could threaten the state or even seize its nuclear arsenal. Pakistani action against militants along its Afghan border is seen as crucial to US efforts to bring stability to Afghanistan, particularly as Washington sends more troops there to fight a raging Taliban insurgency before a gradual withdrawal starts in 2011.