Senate Majority Leader Mitch McConnell is “distressed” over Defense Secretary Jim Mattis’ shock announcement that he will resign over differences with President Donald Trump. Mattis resigned Thursday following Trump’s sudden decision to withdraw U.S. troops from Syria—a move that has been sharply criticized from all sides, except Russia. In a statement late Thursday night, the Kentucky Republican made clear that he sided with Mattis and backed the point made in his resignation letter that the U.S. must prioritize its relationships with its allies. “I am particularly distressed that he is resigning due to sharp differences with the president,” said McConnell, adding: “We must do everything possible to advance an international order that is most conducive to our security, prosperity and values, and we are strengthened in this effort by the solidarity of our alliances.” Trump targeted McConnell via Twitter early Friday, saying the Senate majority leader should “fight for the Wall and Border Security as hard as he fought for anything. He will need Democrat votes, but as shown in the House, good things happen.”