OTTAWA -- The unfolding crisis in Afghanistan continues to dominate discussions along the federal election campaign trail as Canada marks the end of its evacuation efforts in Kabul.

The last Canadian plane left the Kabul airport Thursday morning, government officials said, leaving behind Afghan and Canadian nationals fleeing the ruling Taliban who couldn’t get on a flight out of the country. Soon after, at least two explosions near the airport left more than a dozen people dead, according to reports from Russia's Foreign Ministry.

Liberal Leader Justin Trudeau said it’s “a very difficult day,” but the work in the country isn’t done.

“We have been working day and night over the past months, past weeks to get as many people out as possible. So I understand the heartbreak to those who were not able to get out as the temporary air bridge is closing,” he said.

“We will continue to work with partners, with allies, with regional partners to make sure we’re continuing to do everything we can both to bring tens of thousands of Afghans with their families to Canada, but also to keep putting pressure on the Taliban to ensure that people can leave Afghanistan.”

Since the U.S. first announced the end of its 20-year mission, and its subsequent Aug. 31 evacuation deadline, the situation across Afghanistan has quickly deteriorated, faster than many anticipated.

Canada has evacuated approximately 3,700 individuals to date but has committed to resettle 20,000 in the coming months and years. Government officials said some Canadians and their families remain trapped in Afghanistan, and they are being urged to exercise “great caution.”

On Thursday Gen. Wayne Eyre, the acting chief of the defence staff, said Canada would have liked to evacuate more, but the situation was becoming increasingly dangerous.

“We wish we could have stayed longer and rescued everyone who was so desperate to leave," Eyre told reporters.

"That we could not is truly heartbreaking. But the circumstances on the ground rapidly deteriorated. Now this is an extraordinary humanitarian crisis. But make no mistake: this is a crisis of the Taliban's making."

Trudeau has received daily briefings about the situation in Afghanistan, often delaying his campaign press conferences, and has faced questions almost daily about the government’s evacuation efforts.

Meanwhile, opposition leaders have wasted no time criticizing the government’s response.

“Literally for months and in some cases for years, we’ve been pushing the government to act, get people out that are at risk, work with our allies to help people that are at risk or displaced,” O’Toole said Thursday.

“Mr. Trudeau has wasted months with inaction and has now put us into an election when the situation has been in chaos. It’s heartbreaking and that’s another reason why we need leadership.”

NDP Leader Jagmeet Singh called the government’s withdrawal process a “failure.”

“It’s with a heavy heart that we now see thousands of our allies – people that put their lives at risk to support our troops – now being left behind. So yes, it’s sad to say that Canada has failed and Justin Trudeau knew about this problem, knew about the concerns and didn’t act in a timely way and as a result there’s going to be lots of people now that are pretty desperate and not sure what’s going to happen to them,” Singh said on Thursday.

Green Party Leader Annamie Paul called on her opponents to immediately suspend campaigning for 24 hours to focus squarely on the situation.

“I’m asking that we do the right thing, suspend our campaigns so that we can all concentrate our attention on where it should be which is figuring out how we can rescue those that have been left behind,” she said. “I think it's very important that we make no mistake that this was foreseeable, this was avoidable and it’s a national shame that we have ended our evacuations knowing that we have left thousands and thousands behind."

Paul had previously requested an "emergency recall" of the House of Commons to address the crisis despite it not being possible given Parliament was dissolved when the election was called.

Global Affairs Canada announced Thursday that it is sending $50 million to help with the initial response to the humanitarian crisis in Afghanistan, and will be “ready to respond to further United Nations or Red Cross appeals.”

The statement notes that the government will work with “trusted” organizations on the ground such as the World Food Programme, and the United Nations Office for the Coordination of Humanitarian Affairs to deliver the funds.

“Our partners will employ mitigation measures to ensure the assistance reaches the most vulnerable and is not diverted to other actors or for other purposes. With Canada’s support, humanitarian partners will provide life-saving assistance, such as food, support for health care, clean water and sanitation, ” the statement reads.