Russia used the first round of talks with the US over ending the war in Ukraine to demand the withdrawal of Nato forces from the alliance’s eastern flank, triggering concern in European capitals that the Trump administration could acquiesce to seal a peace deal.

Cristian Diaconescu, the Romanian president’s chief of staff and adviser for defence and national security, said on Wednesday that the US delegation had rejected Moscow’s demand, but that there were no guarantees that Washington would not eventually make this concession to Vladimir Putin.

“As far as I understand, the situation can change from hour to hour or from day to day,” Diaconescu told Antena3 television, in a reference to Donald Trump’s scathing criticism of the Ukrainian leader and his concessions made to Russia even before talks began.