At least four people, including two soldiers, a policeman and a civilian, were killed Wednesday in a suicide bomb attack on a security checkpoint in northwestern Pakistan, security officials confirmed.

It was the second attack to hit Pakistan in as many days.

The bombing took place in North Waziristan, a district in Khyber Pakhtunkhwa province that borders Afghanistan and is a former stronghold of the armed Pakistani Taliban group, also known as Tehreek-e-Taliban Pakistan or TTP.

A number of civilians were also wounded in the attack, according to Rehmat Khan, a local police official.

No one claimed responsibility for the attack but suspicion is likely to fall on the Pakistani Taliban.

In the last six months, the TTP has stepped up its attacks since it unilaterally ended a cease-fire with the Pakistani government, brokered by neighboring Afghanistan last year.

Also Wednesday, the TTP claimed responsibility for an attack the previous day on an oil and gas plant in Hangu, a district in Khyber Pakhtunkhwa, on the border with Afghanistan.

Four security troops and two private guards were killed in the attack on the facility run by a multinational European company, MOL Pakistan Oil and Gas.

Though a separate group, the TTP remains a close ally to the Afghan Taliban, who took over Afghanistan in August 2021 following the withdrawal of U.S. and NATO forces from the country after two decades of war. The takeover some say has emboldened the TTP in Pakistan.