Suicide bombers driving vehicles filled with explosives slammed into a security installation in northwestern Pakistan on Tuesday, killing at least 13 civilians, including six children, and five soldiers, police, rescue services and the military said.

The blast brought down the roof of a nearby mosque soon after residents had broken their fast during the Muslim holy month of Ramadan in a market teeming with shoppers, a military official said on condition of anonymity.

“The assailants sought to breach the cantonment’s security; however, their nefarious designs were swiftly and decisively foiled by the vigilant and resolute response of Pakistan’s security forces,” Pakistan’s media agency said in a statement on Wednesday.

The military said five soldiers were killed. Four suicide bombers were among 16 militants also killed in the attack, it added.

There was no immediate claim of responsibility. Recent years have seen growing attacks by the Pakistani Taliban known as Tehreek-e-Taliban Pakistan (TTP) Islamist militant group on police and military in areas near the Afghan border.

The military said 13 civilians died in the attack.

At least 30 people were wounded, said Muhammad Nauman, a spokesperson for a nearby hospital, all of them civilians caught under collapsed buildings and walls.

The number of children killed was revised down to six on Wednesday from seven in a hospital list the previous day, Nauman added.

Rescue services said they were searching for more casualties under the debris of collapsed buildings. Video images from the scene showed people sifting through piles of bricks and clearing metal scaffolding.

"The evil ambitions of the enemies of Pakistan will never be allowed to succeed," Prime Minister Shehbaz Sharif said in a statement condemning the attack.