Donald Trump’s negotiating team must not be made up of “choir boys” who fall into the Kremlin’s traps through a lack of preparation and experience, an official who observed previous ceasefire talks with Moscow has warned.

The US negotiators will be ruthlessly exploited by their Russian counterparts if they prioritise speed over a durable agreement, said the official, who was close to the implementation of the 2014 Minsk Agreement, which reduced fighting between Ukraine and Russia but failed to end hostilities or prevent the outbreak of a wider war.

Mr Trump issued a call for Ukraine to hold elections before the agreement of a ceasefire, after a US delegation met with Russian officials for the first official talks in Riyadh on Tuesday. It sparked accusations that the US president was adopting Moscow’s key demands before serious negotiations had even begun.

On Wednesday, the president added that “Zelensky better move fast or he is not going to have a country left”.

In Moscow, Vladimir Putin reminded Mr Trump that he had promised to end the war in “24 hours” and urged the president to “go faster” in an interview with local television.