European Union leaders expressed deep doubts on Friday about whether British Prime Minister Theresa May can live up to her side of their Brexit agreement and they vowed to step up preparations for a potentially-catastrophic "no-deal" scenario.

May cancelled a Brexit vote in the UK Parliament this week after it became clear the assembly would reject the deal she concluded with the EU last month. She travelled to Brussels in hope of wringing some concessions from her European partners that would help assuage doubts about the draft divorce agreement back in London.