President Donald Trump on Wednesday lashed out at Ukrainian President Volodymyr Zelenskyy, saying the Ukrainian leader is prolonging the “killing field” after he pushed back on ceding Crimea to Russia as part a potential peace plan.

Zelenskyy on Tuesday ruled out the idea of Ukraine ceding territory to Russia as part of any agreement before high-level talks set for Wednesday in London among US, European and Ukrainian officials. “There is nothing to talk about — it is our land, the land of the Ukrainian people,” Zelenskyy said.

During similar talks last week in Paris, US officials presented a proposal that included allowing Russia to keep control of occupied Ukrainian territory as part of a deal, according to a European official familiar with the matter who was not authorised to comment publicly and spoken on the condition of anonymity.