The Russian military said on Wednesday it was closely watching the situation around Syria and was aware of the movements of a USA naval strike force headed for the Gulf.
"We're rapidly reaching an understanding of what happened on the ground", she added.
Trump's message on social media comes after an alleged chemical weapons attack on Syrian civilians in the rebel controlled town of Douma on April 7th.
Trump has suggested that he has little doubt that Syrian government forces are to blame for what he says was a chemical attack, but neither he nor other administration officials have produced hard evidence.
Last week, Trump advocated pulling US troops out of the country altogether, a drastic move strongly opposed by top military officials.
The global chemical weapons body has sent a team to the site in Douma. They believe that could revive ISIS in the region and actually Turkey is another element within that because we have Turkish President Erdogan announce that after the summit between Russia Turkey and Iran that they would move towards eradicating all "terrorists" the Kurdish terrorists in his view which just about covers all of northern Syria and that certainly would curtail ISIS or give ISIS the grounds to reemerge in the region, it would be insane to move out of Syria for that reason. "And if he does, it's going to be very tough, very tough".
-Russian relations are at their lowest point ever, including the saber-rattling Cold War years of six decades ago. Gen. Valery Gerasimov, chief of the General Staff of the Russian armed forces, has said the military would hit back if US airstrikes endangered Russian servicemen in Syria.
The apparent decision by the White House to conduct a missile strike comes after Russian Federation claimed the Syrian government shot down several Israeli cruise missiles over the weekend.
As it looked to head off the threat of Western strikes, Syria said it had invited the OPCW to visit the site of the alleged attack in Douma, a town in the Damascus suburb of Eastern Ghouta that is on the verge of falling to the regime after a long and bloody siege.
Britain's Parliament is in recess until Monday.
With renewed U.S. military action seemingly imminent - and as Trump threatened that the USA missiles would be "nice and new and 'smart!'" - both Washington and Moscow raised the rhetorical stakes.
"The use of chemical weapons can not go unchallenged". He also reaffirmed his support for an OPCW investigation.
The OPCW did not immediately respond to a request for comment.
Trump has been weighing his course of action in Syria following the suspected chemical attack, which he described as "sick" over the weekend.
Instead, they have in recent investigations gathered blood samples from victims and interviewed witnesses outside Syria.
State news agency RIA Novosti on Wednesday quoted Andrei Krasov, deputy chairman of the State Duma's defense committee, as saying that Russian Federation will treat a US airstrike on Syria "not just as an act of aggression but a war crime of the Western coalition".
And while he did not set a timeline for the withdrawal, he's told his top military advisers he wants the ISIS battle to conclude within six months and American servicemen to return.
He went on to warn that Russian Federation could target the "sources from which the missiles were fired" - which could include United States warships, submarines and aircraft.
Trump then struck a more conciliatory tone regarding Russian Federation.
The Sound and Picture Organization, an activist collective in eastern Syria, said that Iranian fighters and members of Lebanon's Hezbollah group have evacuated their positions in the Boukamal area, near the Iraqi border, which was recently retaken from the Islamic State group.
Russian Foreign Minister Sergei Lavrov said the strike on the T-4 base was a unsafe development. It has since spiralled into a complex war involving world powers.