From the London Mail [caution, tabloid]:
[According to a lip reader, after greeting the king Tuesday] Trump then changed the subject, telling the King he had been in contact with the Russian leader.
‘So right now, I am talking to Putin,’ Trump said. ‘He wants war.’
King Charles said they would discuss that topic later.
‘We will discuss that later,’ the King replied.
But Trump continued.
‘I’ve got a feeling… if he did what he said, he will wipe out the population,’ Trump warned.
The monarch tried to switch topics again.
‘Another time,’ King Charles said.