Bomb in Pakistan kills 3 US soldiers, 3 children

A bomb planted outside a girls' school killed three US soldiers in northwest Pakistan on Wednesday, the army said, in an area that had been largely cleared of Taliban militants.

In scenes that have become familiar in the battle between Taliban militants and the state, a young girl trapped below the stones of a collapsed wall cried out for help.

Three children and a Pakistani paramilitary soldier were also killed and 45 people were wounded in the blast near Swat Valley, where the government mounted a crackdown nearly a year ago it said had cleared out al-Qaeda-linked Taliban.

The blast, triggered by a remote-controlled device, was a grim reminder of the resilience of Taliban militants determined to topple the government of president Asif Ali Zardari, a deeply unpopular pro-American leader.

Pakistan's Taliban have bombed markets, schools and military and police facilities despite major government security crackdowns that have destroyed some of their bases and US drone aircraft attacks that have killed their leaders.

The three US soldiers were part of a small unit that trains Pakistani Frontier Corps responsible for security in northwestern areas near the Afghan border seen as part of a global militant hub. The United States Embassy said it would release a statement later on Wednesday.

After Wednesday's attack which left a crater outside the school, an elderly man walked through the destruction holding a pile of books as soldiers stood by.

Resident of the town of Timergara tried to rescue school girls in blue uniform trapped below rubble. Others helped carry away the wounded.

The appearance of Pakistani Taliban leader Hakimullah Mehsud, in a farewell video with the suicide bomber who killed seven CIA employees in Afghanistan in December, suggests the group poses an increasingly complex threat to Pakistan's security.

The United States is leaning heavily on long-time ally Pakistan to help it stabilise Afghanistan, a top foreign policy priority for president Barack Obama.

It wants Islamabad to eliminate al Qaeda and Afghan Taliban militants who cross over the border to attack US- and Nato-led troops in Afghanistan.

But the nuclear-armed country is focused on fighting homegrown Taliban who have blown up dozens of girls' schools and publicly flogged and executed those deemed immoral, an austere interpretation of Islamic rule they want to impose.

The possibility that some of his aides will be prosecuted under revived corruption charges and growing public frustrations with a sluggish economy and chronic power cuts have also piled pressure on Zardari.

Pakistani foreign minister Shah Mehmood Qureshi condemned Wednesday's bombing in the district of Lower Dir. He said "terrorism will never be allowed to succeed in its nefarious designs".

US drone strikes in northwest Pakistan have intensified since the attack on the CIA in Afghanistan, but analysts say they are unlikely to pose a long-term danger to the Taliban, who seem to carry out suicide bombings at will.

The death toll from drone attacks on Tuesday night — the heaviest ever in terms of the number of missiles fired — has risen to 31, security officials said.