Torkham, the main border crossing between Afghanistan and Pakistan, was shut down on Monday by the Afghan Taliban following a suspected clash between Pakistani and Afghan forces near the normally bustling border transit point.
Residents of the area had on Sunday evening reported hearing heavy gunfire near the border.
The two sides exchanged gunfire after authorities in Pakistan returned an Afghan national who had crossed the border without requisite travel documents.
The return of the Afghan national reportedly irked the Taliban forces who closed the border and opened fire in protest.
Meanwhile, trade activities and pedestrian traffic remain suspended on the first day of the week due to the border closure.
A Pakistani official told AFP the Torkham crossing, equidistant between Kabul and Islamabad, was shut late Sunday after Pakistani officials turned away a traveller accompanying a medical patient.
On Monday at 7:30 am Afghan time (0300 GMT) a “clash took place when Pakistani forces fired at Afghan forces”, Afghan official Harfat Muhajir told AFP.