A bomb rigged to a rickshaw exploded in a bazaar in northwest Pakistan on Tuesday, killing at least nine people and wounding more than two dozen others, police said, in the latest sign of escalating violence in the region bordering Afghanistan.

The attack took place in Lakki Marwat, a district in Khyber Pakhtunkhwa province, local police chief Azmat Ullah said. He said that two traffic police officers and a woman were among those killed.

No group immediately claimed responsibility for the bombing, but suspicion is likely to fall on the Pakistani Taliban, known as Tehrik-e-Taliban Pakistan, or TTP.…