LONDON (AP) — British Prime Minister Theresa May and European Council President Donald Tusk have spoken by phone amid signs of movement in deadlocked Brexit talks.

Tusk tweeted Wednesday that the pair spoke “to take stock of progress in #brexit talks and discuss way ahead.”

Tusk has said he is willing to call a special EU summit if there is movement from Britain to unblock talks.

May’s Cabinet has been inching closer to agreeing a proposal on the key issue of keeping an open Ireland-Northern Ireland border after Brexit.

But some pro-Brexit Cabinet ministers want to see legal advice drawn up by the attorney general before they agree to anything. They fear Britain will be locked permanently into an EU customs union, limiting its ability to strike new trade deals around the world.