Donald Trump has said the US will ‘take a pass’ on a peace agreement between Russia and Ukraine if ‘parties make it difficult’. The US president made the comments to reporters during the swearing-in ceremony for Mehmet Oz as administrator of the Centers for Medicare and Medicaid Services. Trump added that he believed there was a ‘good chance’ of ‘solving the problem’. The US secretary of state, Marco Rubio, had earlier said the US will abandon its efforts ‘within days’ to broker a peace agreement unless there are clear signs a settlement can be reached