U.S. Sen. Chris Murphy is heading across the Atlantic tomorrow for a round of meetings with U.K. and Irish government leaders concerning the problems surrounding the British withdrawal from the European Union, commonly known as Brexit.

The Connecticut Democrat, who is a member of the Senate Foreign Relations Committee, is to meet with officials in London, Belfast and Dublin to discuss the impact of Brexit on transatlantic relations and the unresolved post-Brexit status of the border separating Northern Ireland from E.U. member Ireland. Murphy is also scheduled as a guest speaker on Wednesday at a London School of Economics and Political Science presentation on U.S.-U.K. trade titled “The Dangers of Brexit for the Special Relationship.”

The U.K. was scheduled to exit the E.U. on March 29, but the House of Commons voted to delay the departure after repeatedly rejecting the Brexit agreement negotiated by Prime Minister Theresa May and the E.U. leadership, as well as rejecting a Brexit with no formal withdrawal plan.

Murphy, who has previously stated his opposition to Brexit and called for a new referendum to allow U.K. voters a chance on rejecting their country’s divorce from the E.U., criticized President Trump following a March 14 tweet that said, “My administration looks forward to negotiating a large scale trade deal with the United Kingdom. The potential is unlimited!” Murphy replied to the president on Twitter by complaining, “Trump cheering the breakup of the EU. Congress should not approve a trade deal w Britain unless 1) Brexit fully protects the Irish peace process, and 2) the U.S. completes a trade deal w the EU first.”