MINGORA, Pakistan (Reuters) -- A suspected suicide bomber has killed six people in an attack on a security forces convoy in a market in the main town of Pakistan's Swat valley, police said.
Several more were wounded in the attack, said Farooq Khan, a senior police official in the valley, which has been relatively peaceful over recent months.
"I've seen three vehicles destroyed by the blast," Reuters photographer Hazrat Ali Bacha said by telephone from the site in the center of the town of Mingora.
Shops nearby were also damaged, he said.
In April last year, the military launched a major offensive against Pakistani Taliban militants in Swat, a former tourist valley 120 kilometers northwest of Islamabad, and largely cleared the Islamist fighters out after months of clashes.
The offensive came after Pakistani Taliban militants flocked there to support a radical Muslim cleric trying to impose Taliban-style rule.
The militant takeover of Swat, and their later march into an adjacent valley to the southeast, raised fears for the stability of Pakistan, a nuclear-armed U.S. ally.
The United States at one stage said the government appeared to be abdicating to the militants. But the Swat offensive signaled the beginning of sustained action by the security forces to tackle them.
After Swat was cleared, the army moved into the Pakistani Taliban's main bastion of South Waziristan on the Afghan border in October.
The army has seized most militant bases in the area, an international Islamist hub for Islamists.
The Al-Qaeda-linked Pakistani Taliban, loosely allied with the Afghan Taliban, have launched a wave of bomb attacks in Pakistan in retaliation for the offensives on their strongholds.
Action Against Afghan Taliban
In addition to attacking indigenous Taliban, security forces have also stepped up action against Afghan Taliban on Pakistani soil, arresting at least three senior members in recent weeks.
Among them was the Afghan Taliban's top military strategist, Mullah Abdul Ghani Baradar, arrested this month in a joint Pakistani-U.S. operation in the city of Karachi.
The U.S. special representative to Afghanistan and Pakistan, Richard Holbrooke, last week hailed the arrest of Baradar as a highwater mark for Pakistani-U.S. collaboration.
Although denying support for its old Afghan Taliban allies, Pakistan has turned a blind eye to their members in the belief the Taliban represent the only leverage it has over Afghanistan.
Pakistani cooperation with the United States is a sensitive issue for the government of a country where many people are suspicious of the U.S.-led campaign against militancy.
But despite public reservations, the Pakistani army has been far more robust and cooperative with the United States, analysts have said.
Pakistan wants to play a leading role in any Afghan peace process and keep the influence of old rival India at bay.
Separately, the beheaded body of a Pakistani Sikh man kidnapped about three weeks ago was found on Sunday, a Sikh community spokesman said. His body was found in the northwestern Khyber region.
The spokesman said kidnappers were still holding two other Sikhs and demanding ransom.