"It is clear that any retaliation for the latest use of chemical weapons, possibly the 25th use we have seen recently in Syria, must be bigger than the last retaliation", according to Peter Roberts, another analyst at the Royal United Services Institute.
According to a statement of the French presidency, Macron calls for dialogue between France and Russian Federation to "continue and intensify" to bring peace and stability to Syria.
The Syrian government had strongly rejected those allegations, calling on the Organization for the Prohibition of Chemical Weapons (OPCW) to promptly investigate.
In a response to Russia's threat, President Trump tweeted the following message: "Russia vows to shoot down any and all missiles fired at Syria".
French President Emmanuel Macron on Thursday said France has proof that the Syrian government launched chlorine gas attacks and that France would not tolerate "regimes that think everything is permitted".
But there are also pressures on Washington not to go as lightly as previous year on any retaliation for the Douma attack.
"This is grotesque", Pierce told reporters as she left an emergency meeting of the U.N. Security Council.
Worldwide chemical weapons experts based out of the Netherlands are travelling to Syria to investigate the attack, in which dozens - including children - died, reportedly due to a combination of chlorine gas and the nerve gas Sarin.
Trump orders strikes against Syria over chemical weapons attack
Mrs May is reluctant to ask the USA to hold off any action until she has the opportunity to consult MPs, the BBC understands. The operation by the three allies came after a poison gas attack in Syria that killed at least 60 people last week.
Albania's Foreign Ministry said Le Drian canceled a trip there planned Friday "due to worldwide developments in the security field".
"The Syrian government denies responsibility".
He has cemented his control over most of the western, more heavily populated, part of the country, with rebels and jihadist insurgents largely contained to two areas on Syria's northern and southern borders.
A child is treated in a hospital in Douma, eastern Ghouta in Syria, after what a Syria medical relief group claims was a suspected chemical attack.
Moscow, he said, has "irrefutable information that it was another fabrication".
April 14 (ANI): Cautioning the United States, France and Britain over the military strikes on Syria, the Russian Ambassador to the United States Anatoly Antonov has warned that such actions will not be left without consequences.
Military planners are trying to identify suitable targets that will inflict sufficient pain to make the point without triggering a Russian response, an exercise that is reported to involve consulting Moscow.
Earlier on Friday, Russian Foreign Minister Sergey Lavrov said the suspected chemical attack was fabricated with the help of an unspecified foreign intelligence agency, without naming the country. "No nation can succeed in the long run by promoting rogue states brutal tyrants and murderous dictators", Trump said.