A suicide bomber killed at least 22 Pakistani border guards today in an attack at the main crossing point into Afghanistan, government officials said.
The attack raises fears that Pakistani Taliban militants, who officials say have been in disarray since the killing of their leader, Baitullah Mehsud, in a US missile strike on August 5th, are hitting back against security forces.
"It was a suicide attack and so far we know 22 policemen were killed," said government official Manzoor Hussain.
An intelligence official in the region also said 22 people had been killed in the attack at the Torkham border crossing.
"They were sitting down to break their fast when the attacker walked up," said the intelligence official, who declined to be identified, referring to the end of fasting at sunset during the Muslim holy month of Ramadan.
Pakistan has been hit by a series of suicide bomb attacks over the past two years, launched by al-Qaeda-linked militants fighting the government because of its support for the US-led campaign against Islamist militancy.
Security forces have made significant gains in an offensive against the Pakistani Taliban in the Swat valley, northwest of Islamabad, since late April, and have also been attacking Taliban chief Mehsud's men in the South Waziristan region on the Afghan border.
Earlier today, two missiles believed to have been fired by a US drone struck a suspected militant hideout killing six fighters in South Waziristan, intelligence officials said.
The Taliban had been denying Mehsud's death for weeks, but on Monday two of his aides, Hakimullah Mehsud and Wali-ur-Rehman, confirmed their leader had been killed.
Hakimullah, who led militants in the Khyber, Orakzai and Kurram ethnic Pashtun tribal regions, has been picked as the new overall commander of the Pakistani Taliban.
Security officials have been saying they were expecting reprisal attacks by Hakimullah's men and today's blast in Khyber would appear to indicate he is determined to press on with the fight against the government.