U.S. President Donald Trump said on Saturday there was no need to keep Canada in the North American Free Trade Agreement and warned Congress not to meddle with the trade negotiations or he would terminate the trilateral trade pact altogether.

“There is no political necessity to keep Canada in the new NAFTA deal. If we don’t make a fair deal for the U.S. after decades of abuse, Canada will be out,” Trump said on Twitter.

“Congress should not interfere w/ these negotiations or I will simply terminate NAFTA entirely & we will be far better off,” he added.

Trump on Friday notified Congress of his intent to sign a bilateral deal with Mexico, after contentious talks with Canada ended on Friday without a deal to revamp NAFTA. Trump had unveiled a deal with Mexico on Monday.

Lawmakers on Friday warned that a deal with Mexico could struggle to win approval from Congress unless Canada was also included. Support from Democrats would be needed to pass a purely bilateral deal, they said.

Trump on Monday threatened to slap tariffs on Canadian-made cars if Canada did not join the talks to revamp NAFTA, which he has repeatedly criticized. Trump on Saturday, in his Twitter posts, reprised his attacks that NAFTA has resulted in a loss of U.S. jobs and business.