U.S. President Donald Trump said he would impose 35 per cent tariffs on Canada starting Aug. 1, upping pressure on Ottawa as it seeks to secure a deal with the U.S.

In a letter posted on his social media site Truth Social on Thursday evening, Mr. Trump said he would increase the tariffs that were imposed in February and currently stand at 25 per cent. Mr. Trump ostensibly imposed the levies to push Canada to do more to address U.S complaints about fentanyl trafficking.

“If Canada works with me to stop the flow of Fentanyl, we will, perhaps, consider an adjustment to this letter. These Tariffs may be modified, upward or downward, depending on our relationship with your Country,” Mr. Trump said.