Addressing the possibility of a USA strike, he added, "I want to hope that all countries will avoid steps which essentially haven't been sparked by anything and which may destabilize the fragile situation in the region".
President Vladimir Putin's spokesman Dmitry Peskov said in televised remarks that "we don't participate in Twitter diplomacy".
The Syrian foreign ministry accused the U.S., which has supported some rebel groups in Syria's conflict, of using "fabrications and lies" as an excuse to hit its territory.
In response to the tweet, Russian Foreign Ministry spokeswoman Maria Zakharova said a looming missile strike would be counterproductive and prevent inspectors from investigating the site of the attack.
Russia's diplomat to Lebanon Alexander Zasypkin pointed out that Russian Federation will react to pretty much any U.S. missiles launched in neighbouring Syria by shooting all of them down, as well as targeting their launch locations. Trump's warning was in response to an earlier threat by Russian Federation to shoot down any missiles America launches into Syria. Referring to Moscow's alliance with Assad, he wrote, "You shouldn't be partners with a Gas Killing Animal who kills his people and enjoys it!"
Tuesday, draft resolutions by United States & Russia, to establish or approve Russian investigators in order to study chemical substance weapons attacks within Syria, both of these requests failed to successfully pass in the United Nations Security Committee.
NWS: Slightly warmer, sunny on Virginia Peninsula Wednesday
In the metro area today and Thursday , expect mostly to partly sunny skies with high temperatures in the lower 60s to mid-70s. Friday and Friday night , there are chances for showers and thunderstorms with a daytime high around 70 and a low around 35.
U.S. Defense Secretary Gen. Jim Mattis, striking a cautious tone hours after Trump's threat of missile strikes, said the United States was assessing intelligence about the suspected attack.
Trump had threatened military action following a suspected chemical attack on the rebel-held town of Douma, near Damascus, on Saturday that activists say killed at least 40 people, many of them children.
Officials of the Trump administration have been discussing with officials of France and Britain a possible joint military response to Syria's alleged poison gas attack. President Bashar al-Assad's government - which receives military backing from Russian Federation - denies being behind any chemical attack, a BBC report said.
The White House says President Donald Trump has decided not to attend a summit in South America this week to remain in the U.S.to manage the crisis.
By inviting the worldwide chemical weapons watchdog to send a fact-finding mission to Syria, the government claimed it proved it was innocent of the allegations of using chemical weapons.
Syria and its ally Russian Federation deny such an attack happened.