"An emergency has been declared in the hospital in Swat."

US visit

The attack comes as two US senior commanders, including Mike Mullen, the chairman of the US joint chiefs of staff, visit Islamabad seeking more military operations in the northwest of Pakistan.

There have been numerous clashes and bombings in Swat Valley since Maulana Fazlullah, apro-Taliban leader, launched a campaign to enforce the Sharia (Islamic law) in the region last year.

Asif Ali Zardari, the Pakistani president, who is in London visiting Gordon Brown, the UK prime minister, pledged to combat militancy that has been plaguing the country and neighbouring Afghanistan.