Pakistan to start expelling undocumented immigrants from November 2

Islamabad announced the plan earlier this month, saying Afghan nationals had been behind attacks, smuggling and other crimes in its territory.

Pakistan will start rounding up and expelling undocumented immigrants, including hundreds of thousands of people from neighbouring Afghanistan, on Thursday, the caretaker government's interior minister said.

Afghan refugees wait at the Karachi bus terminal to depart for Afghanistan, in Sindh province. (AFP)

Islamabad announced the plan earlier this month, saying Afghan nationals had been behind attacks, smuggling and other crimes in its territory. Kabul dismissed the accusations and rights groups protested, asking Pakistan to reconsider.

"Only two days are left for a voluntary return," Sarfraz Bugti said in a video statement released on Tuesday.

The operation would be "lengthy and gradual", he added without going into further detail on the time frame. "We are not deporting any refugees. Only those who are completely illegal will leave Pakistan."

Pakistan is home to more than 4 million Afghan migrants and refugees, about 1.7 million of them undocumented, according to the interior ministry.

Islamabad has said Afghans were involved in 14 suicide attacks this year and has accused militant groups operating in its territory of training fighters over the border.

Bugti said those leaving voluntarily will be assisted by the government at temporary centres.

"We will try to provide them food and health facilities for two to three days," he added.

Western embassies and the United Nations have urged Pakistan to identify and protect Afghans at risk of persecution at home.