Suicide bomber kills 12 in Pakistan's Peshawar

PESHAWAR, Pakistan (Reuters) - Pakistani warplanes and artillery pounded a Taliban stronghold on Friday, as a suicide bomber killed 12 people in the city of Peshawar in the latest in a bloody wave of militant attacks.

In a show of unity in advance of an expected ground offensive against the Pakistani Taliban in their South Waziristan lair, government, military and political party leaders vowed to root out militancy and restore the writ of the state.

The army has been stepping up its air and artillery attacks in recent days to soften up the militants' defences while civilians have been fleeing.

The militants have launched a string of brazen attacks in the past 11 days, striking at the United Nations, the army headquarters, police and the general public, killing about 150 people in an apparent effort to stave off the army assault.

"The national consensus is reaffirmed to establish and maintain the writ of the state to weed out these elements," Prime Minister Yusuf Raza Gilani's office said after army chief General Ashfaq Kayani briefed government and party leaders.

The militants posed a serious threat to the sovereignty and integrity of the state, it said. There was no detail about the timing of an offensive which the government says is imminent.

Friday's blast was outside an office of the police's Central Investigation Agency in the capital of North West Frontier Province, a staging post for U.S. supplies into Afghanistan.

Police said a woman appeared to have been involved in the attack, while provincial Information Minister Iftikhar Hussain said the bomber drove up to the police office.

A hospital official said 12 people had been killed and about a dozen were wounded. Television showed anxious policemen wheeling bloodied colleagues into hospital.

Nuclear-armed Pakistan is under U.S. pressure to crack down on Islamist militancy as President Barack Obama considers a boost in troop numbers fighting in neighbouring Afghanistan.

Aircraft and artillery struck militant positions in their strongholds of Ladha, Makeen and in the mountainous Shahoor region of South Waziristan overnight, hours after killing 27 militants in the region in strikes.

"We could see thick smoke and flames leaping into the sky from caves in the mountains after the bombing," said a resident near Shahoor. There was no information about casualties.

Later, militants fired rockets at a military camp, killing three soldiers, intelligence officials said.

"SOME FLEEING"

An army official in the region said some Taliban were trying to leave the area in disguise ahead of the offensive.

"They are now trying to run but we have tightened controls around their areas," said the military official in Wana, the main town in South Waziristan.

The army says about 28,000 soldiers are in place to take on an estimated 10,000 hard-core Taliban. About 500 commandos arrived in the region on Friday, security officials said.

Pakistan's stock market investors have mostly shrugged off the escalation in violence this week, but the market slipped 140 points from an intraday high for the year following the Peshawar blast to end slightly lower at 9,838.12.

Investors would be reassured by an offensive as a sign the government was getting to grips with the militants, dealers say.

More than 80,000 civilians have fled from South Waziristan in anticipation of the offensive and the U.N. refugee agency said more people had left this week.

Pakistani Taliban made advances towards Islamabad early this year, raising fears about the stability of the U.S. ally.

But significant military gains in the Swat valley have reassured the United States and other allies about Pakistan's commitment to the fight.

In a sign of U.S. continuing support, President Barack Obama signed on Wednesday a $7.5 billion (4.5 billion pound) aid bill for Pakistan over the next five years.

But Pakistan's military has complained about the bill because the legislation ties some funds to fighting militants and is seen by critics as violating sovereignty. (Additional reporting by Augustine Anthony and Hafiz Wazir; Editing by Alex Richardson and Jerry Norton)