A bomb planted in a pickup truck ripped through a market in northwest Pakistan Saturday, killing at least 26 people and wounding more more than 50 others.

Authorities say the bomb exploded near a bus stand at a crowded bazaar in Landi Kotal in the Khyber tribal district. Several buildings were damaged in the explosion.

Security officials say the blast appeared to be targeted at members of a tribe allied with the government against the Pakistani Taliban.

No one has claimed responsibility for the attack, but the Pakistani Taliban have carried out hundreds of similar bombings across the country.

Television pictures from the site showed the burned-out remains of a car, market stalls in splinters and a charred building with its front blown off.

Saturday's attack came just one week after another bomb exploded on a bus carrying government workers in Peshawar, killing 19 people.

The United States has criticized Pakistan for not doing enough to rid itself of militants who launch cross-border attacks into Afghanistan.

The Pakistani Taliban, the Afghan Taliban, al-Qaida and affiliated militant groups are entrenched in the tribal regions and take advantage of the porous border to launch attacks against NATO and Afghan forces in neighboring Afghanistan.