A powerful bomb blast ripped through a busy market in an area along the Afghan border Friday, killing at least six people and wounding 15 others, a Pakistani official said.
No one immediately claimed responsibility for the attack in the Khyber, a tribal region whose security is of paramount importance to the U.S. because it is the home of a major supply route for Western troops in Afghanistan. Pakistan's military has mounted several operations in Khyber to drive out Taliban and other Islamist militants.
Local government official Umair Khan said the bomb had been planted near a shop in Khyber's Tirah Valley. The dead and injured had been transported to a hospital, he said.
Khan did not speculate who might have been responsible, but authorities have blamed pro-Taliban militant groups for previous such attacks in the province and elsewhere in the country.
In recent weeks, several major suicide attacks have shaken Pakistan. An attack Thursday killed at least five people in the Swat Valley, which is also in Pakistan's northwest.
Last week, a pair of suicide bombers blew themselves up in the Mohmand tribal region, killing at least 102 people in the deadliest attack in the U.S.-allied nation this year.
The attacks come as Washington is pushing Pakistan to do even more to root out militant groups that use its soil to plan attacks in Afghanistan.