"Russia vows to shoot down any and all missiles fired at Syria", Trump wrote on Twitter.
"You shouldn't be partners with a Gas Killing Animal who kills his people and enjoys it!"
Mr Peskov said the Kremlin was closely following Syria-related announcements from Washington and reiterated a Kremlin call for restraint. "If it's Russian Federation, if it's Syria, if it's Iran, if it's all of them together, we'll figure it out and we'll know the answers quite soon", he pledged Monday.
The attack in Douma happened late on Saturday amid a resumed offensive by Syrian government forces after the collapse of a truce with the Army of Islam rebel group.
Her remarks come as the U.S. is banging the drums of war on Syria over allegations of toxic gas use by the Syrian army against the rebels in the capital Damascus' Eastern Ghouta countryside. That sealed a big victory for Assad, who has now crushed the rebellion in the eastern Ghouta region near Damascus.
So far she has declined to comment on Trump's tweet, but said the use of chemical weapons was a "humanitarian catastrophe" that "cannot go unchallenged".
Doctors and witnesses have said victims showed symptoms of poisoning, possibly by a nerve agent, and also reported the smell of chlorine gas.
Boston Garden chair nets $5800 for Humboldt Broncos fund
Jerseys were worn across the country, with many employers encouraging staff to wear jerseys. Among the fatalities were the Broncos head coach, players and the bus driver.
But his remarks could raise fears of direct conflict for the first time between major powers backing opposing sides in Syria's protracted civil war.
The announcement came on Thursday, just days after the suspected attack which, according to activists and medics on the ground, claimed the lives of more than 85 civilians and injured at least 1,200 people.
Sanders adds that US officials are "continuing to assess intelligence" and are "engaged in conversations with our partners and allies".
The tweet came after Alexander Zasypkin, the Russian envoy to Beirut, said: "If there is an American strike, then we. will shoot down the missiles and target the positions from where they were launched".
On Tuesday evening, NY time, Russian Federation and the United States tangled at the UN Security Council over Syria as they blocked attempts by each other to set up global investigations into the chemical attacks in the war-ravaged country. Russian Federation is Assad's most powerful ally and its devastating air power has helped him wrest back large areas of territory from rebels since 2015.
He said that the US role in Syria is to defeat Islamic State, not "to engage in the civil war itself".
"Due to the recent security situation between US and Syria, and as a precautionary measure", the airline said, "Middle East Airlines will be modifying the routing of some of its flights, which will affect their departure times".
The president has previously dismissed as "fake news" any media reports detailing his intent to oust certain administration officials - including former Secretary of State Rex Tillerson and former National Security Adviser H.R. McMaster - only to follow through weeks later on the plans initially spelled out in news reports.
At stake in Syria is the potential for confrontation, if not outright conflict, between the USA and Russian Federation, former Cold War foes whose relations have deteriorated in recent years over Moscow's intervention in Ukraine, its interference in the 2016 US presidential election and its support for Syrian President Bashar Assad.