ISLAMABAD • Pakistan is pushing for the completion of a fence along its disputed border with Afghanistan - and it wants the United States to help pay for it.

Less than 10 per cent of the fence along the 2,343km of mountainous border with Afghanistan has been completed so far due to financial constraints. Even so, Pakistan Foreign Minister Khawaja Muhammad Asif said the barrier should be finished by the end of 2019.

"It won't cost them much," Mr Asif said of the US in an interview on Feb 2 in Islamabad. "The war is costing them much more."

Pakistan has been under rising pressure to act against the Afghan Taleban and affiliated Haqqani network after US President Donald Trump accused officials in Islamabad of allowing them safe haven.

Last month, Mr Trump suspended about US$2 billion (S$2.7 billion) worth of military aid to the nuclear-armed nation and accused Pakistan of giving "lies and deceit" in return for years of US funding.

The border fence will stop the flow of militants crossing into both countries unchecked, Mr Asif said, adding that Pakistan also considers the return of more than two million Afghan refugees critical for peace.

He urged the US to assist with the fence, and repatriation of Afghan refugees. "It's a free for all," he said, adding that as many as 70,000 people cross the border a day. "These issues are facilitating terrorism."

Pakistan and Afghanistan have denounced each other for harbouring insurgents, prompting relations to drastically sour in the past year.

Afghan President Ashraf Ghani has said Pakistan is waging an "undeclared war of aggression" against his nation.

The Pakistan military has long denied supporting militant groups.

"Any free movement from their side to our side, or our side to their side, can breed mistrust and obviously some terrorist activity on our side or on their soil," Mr Asif said. "It's in our mutual interest that the border is fenced."

BLOOMBERG