Islamabad, Pakistan – A deadline on the validity of legal refugee status for many Afghan residents in Pakistan is due to expire, throwing into doubt the futures of more than a million refugees, many of whom have lived in the country for decades.

The deadline is due to expire on Wednesday, with Pakistan’s federal cabinet expected to discuss the matter during a weekly meeting.

Separately, Afghan Interior Minister Wais Ahmad Barmak and intelligence chief Mohamed Masoom Stanekzai also arrived in the Pakistani capital Islamabad for talks on Wednesday.

Pakistan has extended the validity of Afghan refugees' 'Proof of Registration' (PoR) cards at least six times in the past, but the last extension - granted on January 3, days after the refugees' status expired - was for only a month, the shortest ever awarded.

"Pakistan's economy has carried the burden of hosting Afghan refugees since long and in the present circumstances cannot sustain it further," read a government statement released after that extension.

The refugees have become a bone of contention in the increasing souring diplomatic relations between Pakistan and the United States, with the South Asian country accusing them of being a "security risk".

On Thursday, following a US drone strike in the northwestern Pakistani district of Kurram, Pakistan’s military said that the target had been hiding in an Afghan refugee camp.

"This validates Pakistan's stance that left over terrorists easily morph into Afghan refugees' camps/complexes," the military said in a statement.

"Thus their early and dignified return to Afghanistan is essential."

Refugee push factors

Pakistan is home to at least 1.38 million registered Afghan refugees, according to the UNHCR. There are at least another million refugees estimated to be outside the formal refugee registration system.

"The 2.3 million refugees in Pakistan, it is impossible for all of them to go back immediately," says Baryali Miankhel, the president of an Afghan refugee welfare organisation in the northwestern province of Khyber-Pakhtunkhwa, where most reside. "We have told the Pakistani government this."

Last year, more than 150,000 refugees left Pakistan to return to their native Afghanistan. Of those, more than 59,000 were registered refugees assisted by the UNHCR, while the rest either spontaneously returned or were deported by Pakistan.

UNHCR says it is concerned at the increasingly shorter durations of extensions being offered to Afghan refugees regarding their legal status in the country.

"In terms of the length of time for the PoR extensions, the deadlines that are created for those registered Afghan refugees do create some uncertainty for refugees," Dan McNorton, the UNHCR spokesperson in Pakistan, told Al Jazeera. "That is certainly something that UNHCR has been concerned about in the past, and […] that remains the case."

Refugees themselves testify that the shorter extensions have been leading some to choose to leave the country, despite an uncertain security situation in their home country.

"Refugees are leaving because of the shorter extensions from the government of Pakistan, that is one of the reasons," said Miankhel. "Because there is no peace in Afghanistan, there are no opportunities for employment or even a place to live."

Deteriorating security situation

The security situation in Afghanistan, where US-led coalition forces and the Afghan army continue to battle the Afghan Taliban for control of areas of the country, has been deteriorating in recent weeks.

On Sunday, at least 103 people were killed in a suicide attack in the heart of the capital Kabul.

A day later, at least 11 soldiers were killed when gunmen attacked a military academy, also in Kabul.

Afghanistan and the United States have regularly blamed Pakistan for allegedly providing safe havens to elements of the Afghan Taliban and Haqqani Network armed groups. Pakistan denies the charge, alleging that it is Afghan forces that offer sanctuary to elements of the Pakistani Taliban.

In a rare development, Pakistan's foreign ministry on Tuesday announced that it had handed over 27 individuals suspected of having links to the Haqqani Network and the Afghan Taliban in November.

"Pakistan continues to push any suspected [Afghan Taliban] and [Haqqani Network] elements to prevent them from using our soil for any terrorist activity in Afghanistan," said Muhammad Faisal, the foreign ministry spokesperson.

Asad Hashim is Al Jazeera’s Web Correspondent in Pakistan. He tweets @AsadHashim