President Donald Trump sharply criticized Republican lawmakers who have been actively speaking out against his plans to impose tariffs on countries while negotiating trade deals.

Every time I see a weak politician asking to stop Trade talks or the use of Tariffs to counter unfair Tariffs, I wonder, what can they be thinking? Are we just going to continue and let our farmers and country get ripped off? Lost $817 Billion on Trade last year. No weakness! — Donald J. Trump (@realDonaldTrump) July 25, 2018

When you have people snipping at your heels during a negotiation, it will only take longer to make a deal, and the deal will never be as good as it could have been with unity. Negotiations are going really well, be cool. The end result will be worth it! — Donald J. Trump (@realDonaldTrump) July 25, 2018

Wisconsin Sen. Ron Johnson was particularly scathing in his criticism of Trump, telling Politico, “This is becoming more and more like a Soviet type of economy here: Commissars deciding who’s going to be granted waivers, commissars in the administration figuring out how they’re going to sprinkle around benefits,” in reference to the Trump administration’s plan to distribute $12 billion to farmers affected by retaliatory tariffs.

Johnson was joined by GOP Senators John Thune, Ben Sasse, Pat Toomy, Jeff Flake, and Bob Corker.

Trump’s tweet, however, indicates he is unfazed and is simply using the tariffs as a negotiation tool. The president has said repeatedly he desires free trade but only in a system where both the United States and the opposing country have zero barriers to trade.

His tweet also comes on the day the European Commission President will visit the White House in a bid to head off a trade war.