The tariffs on the three countries, Leavitt said at a White House briefing, were a response to “the illegal fentanyl that they have sourced and allowed to distribute into our country, which has killed tens of millions of Americans”.

At a briefing, Leavitt called the tariffs necessary, citing a failure by the three countries to adequately help the US address problems that have been long-running domestic political issues, and which Trump pledged to fix during his election campaign.

The White House offered limited details on how the levies would be imposed, saying that information would be available for review on Saturday. The tariffs are expected to take effect the same day.

The tariffs would stay in place until significant progress is made in halting the flow of illegal drugs and migrants into the US, the White House said.