Russian Federation said on Saturday it would consider supplying S-300 surface to-air missile systems to Syria following the Western strikes, but this was not discussed at the meeting with Assad, agencies reported.
Incendiary tweets by President Trump warned "Get ready Russian Federation, because they will be coming, nice and new and 'smart!'"
President Donald Trump on Thursday put off a final decision on possible military strikes against Syria after tweeting earlier that they could happen "very soon or not so soon at all".
At the House hearing, Democrats grilled Mattis on the wisdom and legality of Trump ordering an attack on Syria without explicit authorization from Congress. Mattis argued it would be justified as an act of self-defense, with 2,000 US ground troops in Syria; he insisted he could not talk about military plans because an attack "is not yet in the offing".
World Health Organization called on the parties of the conflict to keep their obligation to refrain from attacking medical facilities and personnel as per Security Council Resolution 2286 of the year 2016, which states "any use of chemical weapons to cause harm is illegal under global law".
The Russian Defense Ministry on Friday accused Britain of staging a fake chemical attack in a Syrian town outside Damascus, a bold charge vehemently denied by Britain as a "blatant lie".
This is a big change from Trump yesterday telling Russian Federation to "get ready", but while cooler heads might be getting at least some hearing at these meetings, there's still no guarantee they will ultimately prevail.
She suggested that clarity about USA objectives was necessary to determine the appropriate targets for military action, even as Trump has said he wants United States forces to leave Syria within six months.
They are also said to be considering charging U.S. airlines for using Russian airspace.
"The intelligence provided certainly paints a different picture", Sanders said.
Reuters/APA composite photo of President Donald Trump and Russian President Vladimir Putin.
"We should all be outraged at these horrific reports and images from Douma", said Peter Salama, WHO deputy director general for emergency preparedness and response.
Trump was apparently responding to a statement by Russia's ambassador to Lebanon, Alexander Zasypkin.
"Get ready Russian Federation, because they will be coming, nice and new and 'smart!'".
At the House hearing, Rep. Tulsi Gabbard, D-Hawaii, disputed Trump's legal authority to act without congressional authority and suggested a USA strike would lead to war with Russian Federation.
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.
Iran, the Assad regime's other key ally, called the US -led strikes an "aggression" that was "a flagrant violation of worldwide laws and a disregard for Syria's right of national sovereignty and territorial integrity", according to Iran's semi-official FARS News Agency.
The Syrian-American Medical Society (Sams), which operates in rebel-held areas, and local aid workers said more than 500 people had been treated for symptoms "indicative of exposure to a chemical agent".
British leader May said in London that the West had tried "every possible" diplomatic means to stop Assad from using chemical weapons.
Damascus agreed to hand over its chemical arsenal in 2013, narrowly avoiding American and French air strikes in retaliation for a suspected sarin attack.
France's President Emmanuel Macron says he has "proof" that the Syrian government attacked the town of Douma with chemical weapons last weekend.
The planes fired Storm Shadow missiles at a facility where the United Kingdom said the Assad "regime is assessed to keep chemical weapon precursors stockpiled".
Wednesday:Russia's Foreign Minister Sergei Lavrov said Russian military inspectors found no evidence of a chemical attack.
"Never said when an attack on Syria would take place", said Trump on Twitter.
Earlier on Thursday, Trump said he would spend the day holding several meetings that he expected would lead to a decision "fairly soon".
The French leader previously said any strikes would target the Syrian government's "chemical capabilities".
Senior US military sources say President Assad's forces have already moved some aircraft in an attempt to protect them from attacks.
"France will not allow any escalation that could harm stability in the region", he added.
When Syrian President Bashar Assad's government was teetering on the brink of collapse in 2015, it took Putin just a few weeks to mount a military campaign that saved Russia's longtime ally and eventually turned the tide of war in his favor.
A gas attack in Douma, which killed dozens of people and injured hundreds more including many children on Saturday (April 7), has sparked the row between the two key nations, who have until now appeared to be publicly strengthening their relationship.