At least nine soldiers were killed and 20 others were wounded after a suicide bomber riding on a motorcycle targeted a security convoy in northwest Pakistan on Thursday, the military and three security officials said, a sign of increasing militant violence.

The attack happened in Bannu, a district of Khyber Pakhtunkhwa province bordering Afghanistan, the military said in a statement. It said five soldiers were wounded in the attack.

However, security officials put the number of wounded persons at 20. They spoke on condition of anonymity because they were not authorized to speak to the media on the record.

There was no immediate claim from any group, but the suspicion is likely to fall on the Pakistani Taliban, who have stepped up attacks on security forces since 2022.

Authorities say the insurgents have found sanctuaries and have even been living openly in Afghanistan since the Taliban takeover, which also emboldened them.

Bannu is located near the former militant stronghold of North Waziristan, which served as a base for insurgents until the army years ago announced that it had cleared the region of local and foreign militants.

Occasional attacks have continued, however, raising concerns that the local Taliban, known as Tehrik-e-Taliban Pakistan, are regrouping in the area.

The Pakistani Taliban are a separate group but allies of the Afghan Taliban, who seized power in Afghanistan in 2021 as the U.S. and NATO troops were in the final stages of their pullout.