At least 25 security personnel were killed when between 200 and 300 militants attacked border posts along Pakistan’s border with Agfhanistan, Pakistan’s military said Saturday.

Those who died included Pakistani soldiers and police, the military said in a statement on its website, and two of the seven checkpoints attacked were overrun.

Twenty of the militants, who came from across the border, were reportedly killed, the military said. Reinforcements are now being sent to the northwestern Chitral district.

The attacks took place in areas that spanned roughly 125 km, a military official told CNN.

“It was a well coordinated attack involving a large number of militants,” said the official, who asked not to be named because he’s not authorized to speak to the media.

Earlier, provincial government official Mian Iftikhar Hussain, the information minister for Khyber Pakhtunkhwa province, told CNN that 36 Pakistani security personnel had died. Fifteen militants were also killed, he said.

The militants used both small and heavy weapons, said Rehmatullah Wazir, a senior government official from Chitral.

Wazir said clashes continued between security forces and militants in some areas near the border.

The Pakistani military said the militants were reported to be from Dir, Swat and Bajaur, three areas in northwest Pakistan where the military has sought over the past two years to remove insurgents.

Saturday’s attacks were the latest in a series of recent cross-border assaults from Afghanistan’s Pech Valley and the provinces of Kunar and Nuristan, all areas from which U.S. troops began pulling out earlier this year as part of a strategy designed to bolster security in more populated areas of Afghanistan.

Pakistani military officials say the withdrawal of U.S. troops has provided insurgents in the mountainous areas of eastern Afghanistan with safe havens that are used to launch cross-border attacks against Pakistani security forces.

The attacks have raised tensions between Pakistan and Afghanistan, with each country accusing the other of not doing enough to secure its border region.

CNN’s Nasir Habib and Reza Sayah contributed to this report.