Mr Trump described Syrian President Bashar Al-Assad as a "Gas Killing Animal" and said the US's relationship with Russian Federation was worse than it had ever been in history in a series of furious tweets posted this evening.
President Trump's ominous Wednesday tweets aren't quite the same thing, but they do make one thing clear: The U.S. really, really wants to avoid striking Russian forces in Syria.
Mr Trump said Russian Federation should not be partners with "a Gas Killing Animal", seemingly referring to Syrian President Bashar al-Assad. There is no reason for this.
But Trump reportedly also followed up the warning with communications to Russia to help avoid United States missiles hitting Russian targets in Syria, despite the White House's statement that the USA wasn't afraid to hit them.
In London, Mrs May said all the indications pointed to Syrian government responsibility for the Douma attack.
A similar assessment was delivered earlier today by the Syrian Observatory for Human Rights, a Britain-based war monitor, which said that pro-Syrian government forces were emptying main airports and military air bases.
Trump canceled a foreign trip in order to manage a crisis that is testing his vow to stand up to Syrian President Bashar al-Assad.
Assad's victory in the seven-year civil war "will change the map of the region", and the "biggest loser" will be Israel, she said.
An estimated 500 people were being treated for "symptoms consistent with exposure to toxic chemicals", the World Health Organisation said on Wednesday.
He also said a clash "should be ruled out and therefore we are ready to hold negotiations".
The president's posts cast a Cold War-era chill to some online posters, many of whom mentioned the prospect of a third world war between the USA and Russian Federation - some jokingly, some not.
It added that recent statements from Washington "show (the Trump administration) lacks not only principles and values but also wisdom and logic and that in itself endangers worldwide peace and security".
It prompted a slew of Russian comments that warned that United States strikes could trigger a direct military clash between the two former Cold War adversaries.
"If there is a strike by the Americans, then...the missiles will be downed and even the sources from which the missiles were fired", Zasypkin told the Hezbollah-affiliated Al-Manar TV channel.