The US has expressed concern over the recent clashes at the Torkham border between Pakistan and Afghanistan and asked them to take steps to de-escalate tensions. "We're concerned by the recent clashes at the Torkham crossing point between Afghanistan and Pakistan. We have gotten reports that casualties have been taken on both sides," State Department Spokesman John Kirby told reporters. "We're also concerned about reports of the presence of heavy weapons at the border," he said. Pakistan and Afghan forces exchanged fire on Sunday over construction on the Pakistani side of the border. Torkham is the most frequently used crossing point at Pak-Afghan; most of the terrorists have been found using this gate for entry. "We continue to encourage the governments of both Pakistan and Afghanistan to resolve their disagreements at the crossing point and to de-escalate tensions," Kirby said. Good relations between the two countries are key to the stability to the region, he said in response to a question.