MINGORA, Pakistan (Reuters) -- A militant blew himself up at a police station in Pakistan's northwestern Swat Valley, killing 12 cadets in the second such attack in the area in recent weeks, a senior government official has said.
The military went on the offensive in the region northwest of the capital in late April and has killed or driven out many Taliban militants in what has been widely seen as a successful operation, but the attacks show the militants can hit back.
"Training was going on when a suicide bomber disguised as a recruit walked into the building and blew himself up," Mian Iftikhar Hussain, information minister of the Northwest Frontier Province where Swat is located, told Reuters.
"We have reports that 12 were killed" in the attack in the main town of Mingora, he said.
Prime Minister Yousaf Raza Gilani condemned the killings but said the government was determined to fight militancy.
"We will not allow the enemies of the country to succeed in their evil designs," a statement from Gilani's office quoted him as saying.
Pakistan's military push had allayed fears among its allies, in particular the United States and other countries with troops in neighboring Afghanistan, that the nuclear-armed country was failing to get to grips with spreading Islamist violence.
However, security analysts said militants allied to Al-Qaeda and the Taliban still posed a serious threat to Pakistan.
A suicide bomber killed 22 Pakistani border guards on August 27 in an attack at the main crossing point into Afghanistan at the west end of the Khyber Pass.
It was the first big attack in Pakistan since Pakistani Taliban chief Baitullah Mehsud was killed in a U.S. missile strike on August 5 and raised fears that the militants were hitting back.
Five Pakistan soldiers were killed in a suicide attack at a security checkpoint in the Swat Valley on August 15.
The death of Mehsud, blamed for a series of suicide bombings in Pakistan including the one that killed former Prime Minister Benazir Bhutto in December 2007, is seen as a major blow for the Pakistani Taliban.
The militants appointed Hakimullah Mehsud, a Mehsud aide, as the new leader of an alliance of 13 militant groups known as Tehrik-e-Taliban Pakistan (TTP), or Taliban Movement of Pakistan. The militant group fighting in Swat is also part of TTP.
Hakimullah has been described as a young and aggressive commander and security officials and analysts say it has yet to be seen whether he can keep the TTP as strong and united as it was under Mehsud amid reports of rivalry with a commander who holds sway in Mehsud's South Waziristan stronghold.