Canada and the United States are negotiating a deal that could designate all 8,900 kilometres of their shared border as an official crossing under the Safe Third Country Agreement.

A Canadian government official with knowledge of the talks says Prime Minister Justin Trudeau and President Joe Biden will discuss the issue when they meet in Ottawa on Friday.

The Canadian Press is granting anonymity to the official to discuss matters not yet made public.

The bilateral treaty that Canada and the U.S. signed in 2004 requires asylum seekers to make their claim in the first country they land in, but it only applies to official border crossings.

But thousands of migrants get around the rule by crossing at unofficial locations such as Roxham Road in Quebec so they are not immediately returned to the United States.

There are still many outstanding issues to resolve before the two governments could formally announce a deal, including Canada agreeing to accept a higher number of migrants through official channels.