At least 19 people have  been killed in a suicide bombing in Pakistan, near its border with Afghanistan, government officials have said.

The victims were security personnel gathering for a meal to end the daily fast during the Muslim month of Ramadan, a government official in Jamrud, the main town in the Khyber region, told the Reuters news agency.

The suicide bomber entered the barracks of a paramilitary force in the Khyber district on foot and blew himself up, the official said on Thursday.

Anita McNaught, Al Jazeera's correspondent reporting from Islamabad, said: "The suicide attack took place on the police outpost, this is the main Nato supply route between Pakistan and Afghanistan.

'Taliban-linked attack'

"But what's different is it was not an attack on a Nato convoy in any sense - it was an attack on tribal fighters, tribal policemen ... they are local people paid by the Pakistan government to fight on their behalf and maintain security on this road.

"We have the death, confirmed only this week, of the uniting Taliban leader Baitullah Mehsud.

"Only yesterday was a proper official successor announced, his name is Hakimullah Mehsud. But who is commanding who and who would have given the order to do this, its almost impenetrable at the moment," she said.

Ali Raza, an official in the administration office, said he heard a huge explosion in the building next door.

"We rushed out and saw destruction all around," said Raza, who helped take the wounded to hospital.

Several of the wounded told him the last thing they saw was a young boy approaching security officers with what looked like jugs of water, but no one could confirm he was the bomber.

The Torkham checkpoint marks the main border crossing from the Khyber Pass into Afghanistan.