US President Donald Trump has tweeted that Russia should “get ready” for missiles to be fired at its ally Syria, in response to an alleged chemical attack near Damascus on Saturday.
“Get ready Russia, because they will be coming, nice and new and ‘smart!'” Mr Trump said in his tweet.
Senior Russian figures have threatened to meet any US strikes with a response.
President Bashar al-Assad’s government denies mounting a chemical attack on the rebel-held town of Douma.
In his tweet, Mr Trump called the Syrian leader a “gas killing animal”.
The US, UK and France have agreed to work together and are believed to be preparing for a military strike in response.