Canada has ended its evacuation mission out of Afghanistan, leaving some Canadians and Afghan allies stranded, military officials said on Thursday.

Canadian forces airlifted some 3,700 people from Kabul amid the Taliban's rapid takeover this month.

It is so far unclear how many Canadians remain in Afghanistan.

"Our engagement with Afghanistan is not done," Prime Minister Justin Trudeau said, calling the situation "heartbreaking".

Canada will work with allies in the coming months to try and find safe exits for those still in Afghanistan, he said.

The official withdrawal of Canadian forces came just hours ahead of a bombing at Kabul airport.

Mr Trudeau, who is seeking re-election next month, has promised to resettle 20,000 Afghans in Canada in the coming "months and years".

The evacuation efforts out of Afghanistan come amid a snap federal election, called by Mr Trudeau earlier this month.

The Liberal leader has faced criticism from his political opponents on the campaign trail, who have said that Canada did not act quickly enough to get people out of Afghanistan.

Canada's immigration department has received a total of 2,500 applications - covering 8,000 people - under a special immigration program designed for vulnerable Afghans, including those who assisted the Canadian military.