A Downing Street spokesperson said Mrs May, Mr Trump and Mr Macron had agreed that "reports of a chemical weapons attack in Syria were utterly reprehensible". On Twitter, Trump called the Syrian President a "Gas Killing Animal" and warned that USA missiles "will be coming".
But Trump notably also said there was "no reason for this", reiterated his hope for talks with Putin to halt a new arms race, and blamed his domestic political opponents for poisoning ties.
In a later tweet, Mr Trump claimed that the "bad blood" with Russian Federation was due to the Special Counsel's Russian Federation investigation into meddling in the 2016 United States election.
"The state of the world can not but provoke concern", he said.
"The situation is pretty bad, but it shouldn't be overdramatized", Alexei Malashenko, a leading Russian expert on Syria said in televised remarks.
"The situation in the world is becoming more and more chaotic but all the same we hope that common sense will finally prevail and global relations will take a constructive path", he said.
The request is expected to be honored, since both Syria and Russian Federation said Monday they would welcome a visit and ensure OPCW chemical weapons experts have access to the sites around Douma where chemical weapons were allegedly unleashed on Saturday.
Poznikhir said rebel groups have "incessantly attempted" to use chemical weapons attacks to blame the Syrian government forces, adding that a workshop where militants had loaded ammunition with poisonous chemicals was found in underground tunnels. Paris would be pushing for a strike on the Dumair military airport, which is suspected of having been the launchpad for Saturday's alleged chemical attack.
In response, Russia's Foreign Ministry said, "Smart missiles should fly towards terrorists, not legal government". He said the missiles hit the "sweet spot", doing the expected level of damage while minimizing the unintentional release of toxic fumes that could be harmful to nearby civilians.
Asked about possible US strikes on Syria, President Vladimir Putin's spokesman Dmitry Peskov said Thursday that "it's necessary to avoid any steps that may fuel tensions in Syria".
White House officials said he was staying in Washington to oversee the USA response to Syria. A joint military operation, possibly with France rather than the U.S.in the lead, could send a message of worldwide unity about enforcing the prohibitions on chemical weapons and counter Syria's political and military support from Russian Federation and Iran. -Russian collisions or confrontations in Syrian airspace. The U.S. military fired 59 Tomahawk cruise missiles from the Mediterranean Sea, but the strike had little effect as the air base was up and running in just 24 hours. It is also set to carry out a fact-finding mission in Douma, though it has so far declined to provide a timetable.
Dana W. White, the chief Pentagon spokeswoman, said that to her knowledge no one in the Defense Department communicated with Moscow in advance, other than the acknowledged use of a military-to-military hotline that has routinely helped minimize the risk of U.S.
Russian Federation later hit back, Kremlin spokesman Dmitry Peskov saying "we do not participate in Twitter diplomacy" in comments reported by the Interfax news agency.
A top Russian military official said Russian military police would enter Douma on Friday.
"Never said when an attack on Syria would take place", Trump tweeted. Most have been against the Islamic State terror group.
But petroleum-linked shares rallied as oil prices rose on Trump's Syria statements and after Saudi Arabia intercepted ballistic missiles fired from rebel-held Yemen and shot down two drones.