OTTAWA, Canada: US President Joe Biden and Canadian Prime Minister Justin Trudeau have announced a plan to close a loophole that has enabled thousands of immigrants seeking asylum to move between the two countries along a back road linking New York state to the Canadian province of Quebec.

Despite the Royal Canadian Mounted Police warning that migrants would be arrested if they crossed the border, once they are on Canadian soil they have been allowed to stay and pursue asylum cases.

But under the new policy, asylum seekers who are not US or Canadian citizens and caught within 14 days of crossing anywhere along the 3,145-mile US-Canada border, will be sent back.

Some of the last migrants to cross the border before the Biden-Trudeau announcement were eight people from two families, one Haitian and the other from Afghanistan.

Gerson Solay, 28, carried his daughter Bianca up to the border. He said he did not have the proper documents to remain in the US. "That is why Canada is my last destination," he said, according to the Associated Press before he was taken into custody for processing.

Migrants were previously able to take advantage of a loophole in a 2002 agreement between the US and Canada, which stipulated that asylum seekers must apply in the first country they arrive in. Migrants who go to an official Canadian crossing are returned to the US and told to apply there. But those who reach Canadian soil through somewhere other than a port of entry, are allowed to stay and request protection.

However, critics have said that the new agreement could endanger the safety of asylum seekers by preventing them from accessing needed support from both governments.

The agreement comes as the US Border Patrol responds to a steep increase in illegal southbound crossings along the Canadian border, mainly in northern New York and Vermont along the stretch of border nearest Toronto and Montreal, Canada's two largest cities.

Under the agreement, Canada will allow 15,000 migrants from the Western Hemisphere to seek asylum on a humanitarian basis.