PESHAWAR: A suicide bomber killed four people when he detonated a car bomb at a police checkpoint in a marketplace in northwest Pakistan on Wednesday, reports AFP.

Pakistan is grappling with an uptick in militancy since the Taliban returned to power in neighbouring Afghanistan, although the latest attack has not yet been claimed by any group.

The bomber blew up his vehicle while he was being searched at the check post, he said.

It seems the bomber wanted to reach another destination but blew himself up after he was stopped by police for a routine search.

Another five people were wounded in the blast.

A second police official, Tariq Dawar, confirmed the incident and casualties.

Officials said on Tuesday six security personnel had been killed in a militant siege on a Hungarian-owned oil and gas exploration site around 70 kilometres (44 miles) northeast of Wednesday's blast.

On Monday, officials said unidentified militants detonated explosives in two empty girls' schools in North Waziristan, destroying nine classrooms but leaving no casualties.

North Waziristan has historically been a hive of militancy and was the target of a long-running Pakistani military offensive and US drone strikes during the post-911 occupation of Afghanistan.

The Pakistan Taliban -- known as Tehreek-e-Taliban Pakistan (TTP) -- is the most active group in the region and mostly focuses its attacks on security forces and foreign interests accused of exploitation.

Since the Taliban returned to Kabul in August 2021, Islamabad has said TTP fighters are plotting their attacks from Afghan soil.