President Donald Trump has made repeated threats to make the US neighbour to the north its 51st state.
Mark Carney has been formally sworn in as the new prime minister of Canada, following the resignation of predecessor Justin Trudeau.
Mr Carney, a former governor of both the Bank of Canada and Bank of England, will try to steer his country through a trade war brought by Donald Trump.
Mr Trump has also made repeated threats to make the US neighbour to the north its 51st state.
Speaking at a news conference after the swearing-in ceremony in Ottawa, Mr Carney said such talk was “crazy” and Canada will “never ever be part of the US”.
The American president has slapped 25% tariffs on Canadian steel and aluminium and is threatening sweeping tariffs on all Canadian products from 2 April.
Mr Carney has already said he is ready to meet Mr Trump if he shows “respect for Canadian sovereignty” and is willing to take “a common approach, a much more comprehensive approach for trade”.
The prime minister also said he would keep in place retaliatory tariffs on US goods until the US showed Canada some respect.
Canada, which is the biggest foreign supplier of steel and aluminum to the US, this week announced 25% retaliatory tariffs on those metals along with computers, sports equipment and other products worth $20bn in total.
Canada already imposed tariffs on 4 March worth a similar amount on US goods in response to broader tariffs by Mr Trump.
Mr Carney also said he respects what Mr Trump is looking to accomplish and hopes to have a call with the president.
In the presence of governor general Mary Simon, the personal representative of King Charles, who is Canada’s head of state, the new prime minister took the oath of office.
He plans to visit France and the UK, as Canada seeks to shore up alliances in Europe, with its relations with the US sinking to unprecedented lows.