Ten people were killed and 45 injured on Thursday when a suspected suicide bomber blew himself up at a gathering of tribesmen in a Pakistani region known as a Taliban safe haven, officials said.

The blast targeted a "lashkar" or government-backed tribal force in Batmalai, about 40 kilometres northeast of Khar, the main town in northwest Bajaur on the Afghan border, local official Iqbal Khattak told AFP.

"Ten people were killed and 45 were injured in the suicide attack," he added. Of the injured, 30 were in a serious condition, he added.

One of the dead was lashkar head Malik Fazal Karim, he said.

"Two to three hundred members of the lashkar were finalising their strategy after demolishing houses of militants when the blast occurred," said local police official Fazal-i-Rabi.

Tribal elder and former lawmaker Shahbuddin Khan said: "The blast was suicide."

Pakistani forces have been engaged in fierce clashes with militants linked to the Taliban and al-Qaeda since a military operation was launched in the semi-autonomous tribal region in August.

The Pakistani military said last month that since the fighting began some 1 500 rebels and 73 soldiers had died while hundreds more militants were captured.

On Wednesday, Pakistani fighter jets bombarded several areas in Bajaur, killing 15 militants, local administration official Mohammad Jamil told AFP.

Pakistan's tribal belt became a safe haven for hundreds of al-Qaeda and Taliban extremists who fled Afghanistan after the US-led toppling of the hardline Taliban regime in late 2001 and have since set up training camps here.

Many militants had gathered in Bajaur in recent months after being driven out of other Pakistani tribal regions, especially North and South Waziristan, hundreds of kilometres to the south.

While Pakistani forces have been concentrating on Bajaur, most of recent spates of suspected US missile attacks on Pakistan have focused on Waziristan.

Pakistan has been accused by the United States and Afghanistan of not doing enough to stop militants crossing the border to attack US and Nato troops in Afghanistan.

But Islamabad says its operation in Bajaur is proof that it is committed to crushing insurgents.

Separately on Thursday, suspected militants fired rockets at the airport and blew up the main electricity transmission line in the northwest city of Peshawar, where Taliban- and al-Qaeda-linked extremists are also active.

Local officials in restive Hangu district, also in the northwest, later said an important Taliban commander was freed from custody with three of his men in a prisoner swap with three army soldiers and seven paramilitary troops.

Taliban commander Maulana Rafiuddin was described at the time of his arrest in July as a deputy of the Tehreek-i-Taliban Pakistan (Taliban movement-TTP) leader Baitullah Mehsud.

The security personnel were seized during protests at his detention. Tribal leaders negotiated the swap.

AFP