A U.S. official said the Russians had been warned before the U.S. launched at least 59 tomahawk missiles aimed at Syria.

Pentagon spokesman Captain Jeff Davis said in an official statement: "Russian forces were notified in advance of the strike using the established deconfliction line. U.S. military planners took precautions to minimize risk to Russian or Syrian personnel located at the airfield."

The strikes, which hit an airfield near Homs, struck aircraft and infrastructure including the runway, NBC reported. There is no word on casualties yet, but no people were targeted, the official told NBC.

No Russian assets were targeted, according to the report.

On Thursday, Secretary of State Rex Tillerson said that Russia had failed to carry out a 2013 agreement to secure Syrian chemical weapons, adding that Moscow was either complicit or incompetent in its ability to uphold that deal.

Tillerson said that the U.S. had a high degree of confidence that sarin nerve gas had been used in the Tuesday chemical weapons attack in a rebel-held area of northern Syria hit by government air strikes.

The secretary of state said the U.S. "sought no approval from Moscow" on the strike.

Following the U.S. attack, the head of Russia's upper house of Parliament's defense committee said Moscow would call for an urgent U.N. Security Council meeting, Reuters reported citing RIA. The report also said the lawmaker claimed the U.S. strike could undermine efforts to fight terrorism in Syria.

Russia's deputy U.N. envoy, Vladimir Safronkov, warned earlier Thursday of "negative consequences" if the U.S. carried out military strikes on Syria over the attack.