(CNN) -- Russian President Vladimir Putin has denounced the US strike against a Syrian government airbase as "aggression against a sovereign state in violation of the norms of international law."
Putin believes the attack was done under a "trumped-up pretext," Kremlin spokesman Dmitry Peskov told reporters Friday, according to Russian state-run news agency Sputnik.
In a statement, the Kremlin said Syria "has no chemical weapons," pointing to reports by UN inspectors.
VIDEO: Russia warned of US strikes in Syria in advance
"Vladimir Putin believes that complete disregard for factual information about the use by terrorists of chemical weapons drastically aggravates the situation," the statement said.
"This move by Washington has dealt a serious blow to Russian-US relations, which are already in a poor state."
The Kremlin added that Putin sees the latest US military action as "an attempt to distract from the mounting civilian casualties in Iraq."
It has suspended an October 2015 agreement between coalition and Russian air forces to avoid mid-air incidents.
Lawmaker Viktor Ozerov, head of the Russian Federation Council's defense committee, said the strike "may undermine efforts in the fight against terrorism in Syria."
"Russia will demand an urgent UN Security Council meeting after the US airstrike on a Syrian aviation base," he told state news agency RIA. "This is an act of aggression against a UN member."
The Kremlin is Syrian President Bashar al-Assad's most powerful ally and has provided the military might behind his continuing grip on the country, which plunged into civil war six years ago.
US President Donald Trump ordered the strike against the airbase from where a chemical weapons attack was allegedly launched earlier this week.
No deal
Russian Senator Konstantin Kosachev, who heads the Federation Council's international affairs committee, said the strike dashed any hopes for a US-Russia anti-terror coalition in Syria.
"And it started so well, what a shame," he wrote on Facebook Friday.
"In one way or another, Russian cruise missiles continue to strike terrorists, and American ones strike government forces which, in fact, lead the war against terrorists."
He continued: "I'm afraid that given such an approach, the desired Russian-American anti-terrorist coalition in Syria, so often talked about since Trump rose to power, will repose in the Lord before it has the chance to be born."
Russian Foreign Ministry spokeswoman Maria Zakharova said Friday that Russia is suspending an agreement signed in October 2015 aimed at minimizing risks of in-flight incidents between Russian and coalition aircraft.
"US actions further destroy Russia-US relations. If earlier it was explained using the need to fight against terrorism, now it's an obvious act of aggression against the sovereign state of Syria," she added.
Matthew Chance, CNN's senior international correspondent based in Moscow, said the airstrikes "are an immensely dangerous episode in the relationship between Russia and the United States, not least because they potentially bring into contact Russian forces who are on the ground in Syria and the US forces."
Russia was warned of the attack before it took place, in accordance with deconfliction policies between the US and Russia over military activities in Syria.
Nevertheless, Chance pointed out, Russia did not choose to use surface-to-air missiles systems in place in Syria that are "fully capable of intercepting cruise missiles if they so choose to."
"(This) implies a degree of tacit Russian consent to the strikes," Chance said.
Russian involvement
Ahead of the strike against the airbase, Russian officials warned the US against making any "snap judgments" regarding the chemical weapons attack, which struck a rebel-held town in Syria's Idlib province Tuesday.
Russia has attempted to negotiate ceasefires in Syria, and in January began withdrawing some military forces from the conflict area.
Support from Russian airstrikes for Syrian regime forces have been crucial in helping them to gain the upper hand in the long-running conflict and pushing rebel fighters from the key city of Aleppo in December.
But Russia's next moves are unclear, and prior to the US action, Putin had made it clear he expected Russian involvement to wind down.
The Kremlin has worked closely with Turkish President Recep Tayyip Erdogan, an enemy of Assad, to negotiate ceasefires and bring about a potential diplomatic solution to the conflict.
