Sporadic military bombardments erupted in Pakistan's tribal areas on Tuesday, where security forces are believed to be on the brink of an all-out onslaught to crush Taliban rebels, officials said.
Artillery struck rebel hideouts in districts of South Waziristan, a semi-autonomous northwest tribal region on the Afghan border and stronghold of feared Pakistan Taliban chief Baitullah Mehsud.
"Security forces used heavy artillery to pound militant hideouts. We have reports that several miscreants have been killed but we do not know the exact number," said an intelligence official in the northwest's main city, Peshawar.
A government official based in the area confirmed the strikes, which began overnight and continued into early Tuesday, telling AFP, "They are targeting Kotkai, Spainkai Raghzai and Srarogha areas."
"There is heavy firing since midnight - we can hear it," Spainkai Raghzai resident Aftab Wazir told AFP.
Security forces are already locked in a seven-week campaign against insurgents in three northwest districts, and a governor on late Sunday announced a "full-fledged" second front along the mountainous and wild tribal belt.
North West Frontier Province governor Owais Ahmad Ghani vowed to track down Mehsud, blaming him for a string of recent deadly bomb attacks.
The army has so far stayed silent on any new campaign in the tribal areas and it is not clear when an all-out offensive would begin. They have officially confirmed only some retaliatory strikes in South Waziristan.
In a separate incident on late Monday, a group of Taliban militants attacked a police checkpost in Mardan city, about 45 kilometres (27 miles) northeast of Peshawar, killing one policeman and wounding four others.
"One policeman was killed when a group of some 50 Taliban attacked a police checkpost at Kharakai village," said local police official Asghar Khan.
"They fired rockets, hurled hand grenades and used assault rifles."
Security forces launched their offensive against Taliban fighters near northwest Swat valley on April 26, after the insurgents advanced to within 100 kilometres (60 miles) of Islamabad.