Tensions between the U.K. and the European Union escalated Wednesday after British Prime Minister Theresa May accused European politicians and officials of issuing threats against Britain.

Hours after the EU’s chief negotiator, Michel Barnier, detailed far-reaching demands for the Brexit divorce deal, Mrs. May said they represented a hardening of the bloc’s negotiating stance.

In a televised speech to voters ahead of a June 8 general election, she accused “some in Brussels” of willing the Brexit talks to fail. “Threats against Britain have been issued by European politicians and officials,” she said, without being specific.

Those threats “have been deliberately timed to affect the result of the general election,” she said.

The heightened tensions followed a dinner between Mrs. May and European Commission President Jean-Claude Juncker a week ago.