Twin attacks by militants in restive northwest Pakistan on Wednesday killed at least three police officers and wounded 20 others, officials reported.

The assaults, which occurred hours apart in the Khyber Pakhtunkhwa province, included an ambush on a security convoy and a suicide bombing at a police station.

The first incident took place in the Upper Dir district, where militants ambushed a security convoy. Three police officers were killed and 15 others were wounded in the exchange of fire, according to local police official Ibrahim Khan. Khan stated that security forces returned fire and the engagement was ongoing, but did not immediately confirm if any militants were harmed.

Hours later, a suicide bomber detonated an explosives-laden vehicle at a police station in Bannu, a city also located in Khyber Pakhtunkhwa. This blast injured at least five police officers and caused damage to the station. No fatalities were immediately reported from the suicide bombing.

No group has claimed responsibility for the attacks. However, suspicion is likely to fall on the Tehrik-e-Taliban Pakistan (TTP), also known as the Pakistani Taliban. The TTP, which is separate from but allied with Afghanistan’s Taliban, has been accused by Pakistan of operating from sanctuaries within Afghanistan. Both the TTP and the Afghan Taliban government deny these allegations.

These attacks represent the latest indication of escalating violence in the region that borders Afghanistan.