LONDON — British Prime Minister Theresa May will urge European Union leaders to unite and condemn Russia as leaders of the bloc’s 28 nations meet in Brussels.

May is seeking a strong statement against President Vladimir Putin after the poisoning of a former Russian double agent and his daughter in England. Britain blames Moscow for the nerve-agent attack.

In the wake of the attack Britain has called Russia a growing threat to Western democracies.

On Monday EU foreign ministers expressed “unqualified solidarity” with Britain. But May is hoping for a more strongly worded statement that explicitly condemns Russia.

Brexit is also on the agenda at the two-day summit starting Thursday. Britain hopes the EU will sign off on the terms of the U.K.’s departure next year and green-light talks on future relations.