A surge of asylum seekers from the US has caused strife between Canadian Prime Minister Justin Trudeau and the leader of the most populous province.
Ontario Premier Doug Ford says the province will not pay for the cost of housing the thousands of asylum seekers spilling over the US border.
Mr Trudeau fired back that he had to "explain" how Canada's refugee system works to the newly elected Mr Ford.
Since January, almost 9,500 asylum seekers have been caught at the border.
Mr Trudeau said he had to spend "a little time explaining" how the asylum-seeking system works in his first meeting with Mr Ford since the premier was elected in June.
"The premier asked me a question that a lot of people have asked me: 'Why don't we just stop them at the border? Why don't we just prevent them from crossing?'" Mr Trudeau told CBC Metro Morning on Friday, the day after his meeting.
"We have to provide due process for people according with Canadian law and values."
Mr Ford blamed the federal government's immigration policies on the influx, and said that Ottawa should pay "100%" of the costs associated with housing and providing services to the asylum seekers while they stay in Canada and wait for their refugee claims to be heard.
His thoughts were echoed by others in his party, the Ontario Progressive Conservatives.
"[Trudeau] was the one who tweeted out that everyone was welcome here and as a result of that we've had thousands of people cross the border illegally and it's putting a strain on many of our public resources," said Lisa MacLeod, Ontario's minister of children, community and social services.
To those fleeing persecution, terror & war, Canadians will welcome you, regardless of your faith. Diversity is our strength #WelcomeToCanada— Justin Trudeau (@JustinTrudeau) January 28, 2017
Since Donald Trump was elected, almost 30,000 migrants trying to illegally cross the border have been apprehended by the Royal Canadian Mounted Police (RCMP). Many migrants had tried and failed to get asylum in the US.
Once in Canadian police custody, migrants are allowed to make their refugee claim.
Canadian provinces and cities have scrambled to provide services for this surge of migrants, especially in Quebec, where most border crossings occur.
Montreal had to open its Olympic Stadium as a shelter to house the migrants. Now many are being moved to Ontario - especially to the city of Toronto.
In June, Toronto Mayor John Tory sent a letter urging the federal government for more support.
The letter claimed that there were more than 3,000 refugee claimants and asylum seekers living in shelters and hotels.
The mayor said soon the city may have to turn community centres into additional residences, which would cut back on services for its own citizens.
The federal government has already earmarked C$11m ($8.4m; £6.3m) to help Ontario with housing asylum seekers, but Mr Tory said he needs more like C$64m.
After Mr Ford's statements, Mr Trudeau responded that more help will be on the way.