Kathmandu. U.S. President Donald Trump on Thursday threatened to impose a 50% tariff on all aircraft sold in the United States.

Trump accused Canada of refusing to certify the jets of Georgia-based Gulfstream Aerospace, and said the move could be retaliatory.

In a social media post, Trump said that if Canada does not correct its decision immediately, all Canadian aircraft sold in the United States will be subject to higher tariffs. He also claimed that the process of revoking the certificates of Bombardier’s Global Express business jets has been initiated. According to aviation analytics company Cirium, there are currently around 150 Global Express aircraft registered and operating in the US.

Bombardier and Gulfstream are direct competitors in the commercial jet market. “We take President’s comments very seriously and are in constant contact with the Canadian government,” Bombardier said in a statement. The airline said in a statement that all of its aircraft are fully certified by the US Federal Aviation Administration and that it is expanding its operations in the United States.

A spokesman for the Canadian government did not immediately respond to requests for comment. But John Gradek, an aviation expert at McGill University, said the certification had to do with safety issues and that the cancellation of the certification for commercial reasons would be “unprecedented”. He said the move could be a new sign of extreme pressure in the context of the trade war.

In 2017, during the first Trump administration, the US Commerce Department imposed tariffs on Bombardier, accusing it of improper government subsidies. But the U.S. International Trade Commission later ruled that the Canadian company had not harmed U.S. industry.

According to analysts, if the US market closes for Bombardier, the Quebec-based company will suffer a major financial setback. It is also expected to affect other Canadian aircraft manufacturers and Airbus’ projects in Canada.