The reason is unclear, but former prime minister Stephen Harper is said to be visiting the White House next week.

CTV News reports he didn't notify the current Canadian government of the plan.

Emails say US officials are expecting Harper July 2nd.

That's a day after Canada’s retaliatory tariffs on imports of U.S. goods and American-made steel and aluminum are set to come into effect.

Officials say he's planning to meet with American National Security Advisor John Bolton, who was the U.S. ambassador to the UN when Harper was prime minister.

How long the former PM's visit's been in the works isn't known.

As well, Harper did not reach out to the Canadian embassy in D.C., Global Affairs Canada, or the Privy Council Office.

The visit comes during increased tensions in the Canada-U.S. relationship with the prospect of a full-blown trade war on the horizon, including new tariffs on autos.

U.S. President Donald Trump and his officials have also engaged in personal attacks on Trudeau via televised appearances and social media.

Harper's office had not relpied to a CTV News request for comment.

- With files from CTV News