The US Defense Department withheld $50 million in Pakistan military payments after Pentagon chief Jim Mattis accused Islamabad of not doing enough to counter the Taliban-affiliated Haqqani network, an official said Friday.

“Secretary Mattis told congressional defense committees that he was not able to certify that Pakistan took sufficient actions against the Haqqani network to permit full reimbursement of the fiscal year 2016 Coalition Support Funds,” Pentagon Spokesman Adam Stump said.

The United States had allotted $900m in military aid to Pakistan through the special fund. The country has already received $550m of that, but Mattis's decision means $50m will be withheld. The remaining $300m was rescinded by Congress as part of a broader appropriations act.

“This decision does not reduce the significance of the sacrifices that the Pakistani military has undertaken over previous years,” Stump said. “Pakistan still has time to take action against the Haqqani network in order to influence the secretary's certification decision in FY17,” he added.

Led by Sirajuddin Haqqani, who is also the Taliban's deputy leader, the group has carried out numerous operations deep in the heart of Kabul and has been blamed by Afghanistan for a devastating truck bombing that killed more than 150 people in the capital in May.