Twenty-five people were killed when a bomb targeting a militia opposed to the Pakistani Taliban exploded in a market close to the Afghan border today - the deadliest blast in the country in several months, officials said.
The explosion hit vehicles being used by the militia in the Khyber region, said local security officer Khan Dad Khan.
The army has supported the formation of anti-Taliban militias in north-west Pakistan, but the insurgents have ruthlessly attacked the groups over the last two years. Many of the country's bloodiest bombings have been against militia members or their families.
24 other people were injured in the blast, which is believed to have been detonated by remote control, said local government official Iqbal Khan.
Islamist militants with links to al-Qa'ida have carried out hundreds of bombings in Pakistan since 2007, killing many hundreds of soldiers, police, government officials and civilians.
The Pakistani army has carried out offensives against the militants in their strongholds in tribally administered regions like Khyber, but the insurgents have proven to be a resilient foe.
The violence has triggered fears in the West that nuclear-armed Pakistan may be buckling under extremism.
That said, the frequency of large-scale attacks outside the north-west has decreased over the last 18 months.
The last major bombing was close to the Swat Valley in September, when a suicide bomber attacked the funeral of a tribal elder opposed to the Taliban, killing 31 people.