LONDON (AP) — U.K. Prime Minister Theresa May will have a dinner meeting in Brussels with senior European Union officials on Monday, in hopes of reinvigorating stalled negotiations on Britain's departure from the European Union.

May's unexpected meeting with European Commission President Jean-Claude Juncker and chief negotiator Michel Barnier follows Barnier's warning last week that the latest round of talks ended in a "disturbing deadlock" over Britain's financial obligations to the bloc.

EU estimates suggest Britain must pay from 60 billion euros to 100 billion euros ($80 billion to $120 billion) to settle commitments it has made while part of the EU, including development projects and the pensions of civil servants. Britain has rejected such figures.

The EU is demanding progress on the so-called divorce issues - the financial settlement, citizens' rights and the status of the border between the Republic of Ireland and Northern Ireland — before talks can move on to issues such as future trading and security arrangements. Leaders of other 27 member states are expected to rule this week that there hasn't been enough progress for the talks to move forward.

British Foreign Secretary Boris Johnson on Monday urged the EU to speed up talks and start a discussion of the future relationship with the U.K., which is set to leave the bloc in March 2019. Arriving at a meeting of EU foreign ministers in Luxembourg, Johnson said it was time for the negotiators to get moving and "stop letting the grass grow under our feet."

It is time for "the great ship to go down the slipway and onto the open sea and for us to start some serious conversations about the future and the new relationship," Johnson told reporters.