TORONTO — Fans at a Toronto Raptors game Sunday continued an emerging trend of booing the American national anthem at pro sporting events in Canada.

Fans of the NBA’s lone Canadian franchise booed the anthem after similar reactions broke out Saturday night at NHL games in Ottawa, Ontario and Calgary, Alberta, hours after U.S. President Donald Trump made his threat of import tariffs on America’s northern neighbor a reality.

After initially cheering for the 15-year-old female singer, fans booed throughout “The Star-Spangled Banner” performance. At the end, mixed boos and cheers could be heard before the crowd erupted in applause for the Canadian anthem, “O Canada.”

Trump declared an economic emergency in order to place taxes of 25% on imports from Canada and Mexico and 10% on imports from China. Energy imported from Canada, including oil, natural gas and electricity, would be taxed at a 10% rate.

Canadian Prime Minister Justin Trudeau and Mexico’s president ordered retaliatory tariffs on goods from America in response.

U.S. national anthem boos in Canada are rare, but not unheard of, especially when tied to world events. In the early 2000s, fans at games in Canada booed to show their disapproval of the U.S.-led war against Iraq.

The NHL’s Canucks will host the Detroit Red Wings on Sunday night in Vancouver, British Columbia.