US president Donald Trump warned Russia to prepare for a US strike against Syria, shrugging off a warning from Moscow that it would respond by targeting American “launch vehicles” involved in any military operation that threatened its forces.

“Russia vows to shoot down any and all missiles fired at Syria. Get ready Russia, because they will be coming, nice and new and ‘smart!’ You shouldn’t be partners with a Gas Killing Animal who kills his people and enjoys it!” Mr Trump tweeted on Wednesday morning, in a reference to Syrian president Bashar al-Assad.

His tweet marked a sharp escalation in the war of words between Russia and the US over an alleged chemical weapons attack near Damascus and raised concerns about the risk of military confrontation between the powers following any US strike.