The most specific proof the source could come up with was his observation that Russian Federation has a surveillance drone, which he claimed "flew over the hospital that was treating people injured in the attack". While the source failed to provide any concrete details about the alleged communication - such when it was intercepted or what names or other information it contained - they did note that the United States "did not know prior to the attack it was going to happen".
"We are deeply anxious by our partners in the UN Security Council trying to evade an honest investigation into that episode", he said.
Russian Federation has blamed the attack on anti-Assad rebels.
"Our firepower, our ability to attack the terrorists hasn't been affected by this strike".
Denouncing a "very barbaric" attack, Trump ordered a strike that saw 59 Tomahawk cruise missiles slam into the airbase in central Syria from where Washington accused Assad's forces of launching the attack. "At least we agreed to establish day-to-day on-line dialog on a number of major issues, including the inventorying of the problems that were created by the previous administration in bilateral relations, as well as mechanisms on matters related with the implementation of the agreements we have in the military-political sphere and the mechanisms that are expected to narrow disagreements or improve the understanding of each other's positions on various regional crises, first and foremost, the Syrian settlement".
Korea warns United States not to be militarily adventurous
Previous years have seen grand military parades, mass celebrations and weapons tests conducted on the "Day of the Sun". That attack alarmed the North and was condemned as "unpardonable" by Pyongyang , which counts Syria as an ally.
Also on Wednesday, Russia's representative to the United Nations vetoed a Security Council resolution condemning the attack and calling for an immediate global investigation. "At the right time everyone will come to their senses & there will be lasting peace!"
Lavrov said he emphasized the need for a wide-ranging OPCW probe during Wednesday's talks in Moscow with U.S. Secretary of State Rex Tillerson, suggesting that Western nations, Russian Federation and some regional powers could dispatch additional experts to join the investigation.
Assad said Syria would only allow an "impartial" investigation into the poison gas incident.
Since starting with mass protests in March 2011, Syria's conflict has spiralled into a devastating civil war that has killed more than 320,000 people and forced millions from their homes.
The coalition said Thursday one its air strikes had accidentally killed 18 members of the Syrian alliance south of Tabqa, a strategically important town on the Euphrates River near Raqa.