“They need to tone it down and take a hard look and sign that deal,” Mike Waltz, the White House national security adviser, said in an interview with Fox News.

Pushback from Ukraine on the minerals deal and how Trump is carrying out peace talks is simply unacceptable, Waltz said, given everything the US has done for Ukraine.

Waltz’s comments come a day after Trump and Ukrainian President Volodymyr Zelensky traded insults, with Trump calling Zelensky a dictator and Zelensky saying the US president was living in a disinformation bubble and spewing talking points from Moscow.

However, Waltz said US differences with Ukraine were not irreconcilable, saying: “The president also said how much he loves the Ukrainian people.”

Ukraine and European leaders have balked at being left out of peace talks begun after Trump and Russian President Vladimir Putin spoke by telephone last week.

Waltz denied that US allies and Ukraine were not being consulted.

“There’s a term for this in diplomacy. It’s called shuttle diplomacy, because bringing everybody to the table at once just hasn’t worked in the past,” he said.

“So we’ve engaged one side, we’ve engaged the other side, and then we’re going to have a process moving forward under President Trump’s direction and leadership.”