Russia has diverted a warship to protect the Syrian coast and vowed to bolster Bashar al-Assad's missile defences against more US strikes, risking a confrontation between the former Cold World foes.
The Admiral Grigorevich, a cruise missile-carrying frigate, passed through the Bosporus en-route to Russia's Syrian navy base at Tartus on Friday.
The Grigorevich, which carries Moscow's state-of-the-art Kalibr cruise missiles, was taking part in joint exercises in the Black Sea with the Turkish navy when it was ordered to turn around.
The US on Friday fired dozens of cruise missiles at al-Shayran air base near the western city of Homs from which it said a deadly chemical weapons attack was launched this week.
Dmitry Peskov, a Kremlin spokesman, said President Trump’s decision to directly target the Syrian regime inflicted further "considerable damage" to ties between Moscow and Washington.
"This step by Washington inflicts considerable damage to US-Russia relations, which are already in a lamentable state,” he said.
Mr Peskov said Mr Putin, a staunch ally of the Syrian leader, regarded the US action as "aggression against a sovereign nation" on a "made-up pretext" and a cynical attempt to distract the world from civilian deaths in Iraq.
The Kremlin also announced it was immediately suspending its air safety agreement with the US in response to missile strikes on a Syrian air base.
Comment by the Presidential Press Service on the situation in Syria https://t.co/sRmVRThMP4— President of Russia (@KremlinRussia_E) April 7, 2017
The memorandum, signed in October 2015, is designed to avoid clashes in the crowded airspace over Syria, with each side giving the other warning over planned strikes.
In October, Russia warned that it would use its missiles to intercept any US missiles or jets targeting Syrian forces.
However, they do not appear to have made any attempt to intercept the Tomahawk missiles fired by US destroyers in the early hours of Friday morning.
Six Syrian soldiers were reported to have been killed in the missile strike, which destroyed as much as 90 per cent of the base. No Russian soldiers or equipment were reported to have been damaged in the attack.
It is reported that the US informed Russia of its plans to strike hours ahead, giving them time to remove any aircraft they had stationed at the base.
However Dmitry Medvedev, Russian Prime Minister, complained that America had been “one step away” from clashing with the Russian military.
A US defence official insisted the attack was a "one-off," meaning it was expected to be a single strike with no current plans for escalation.
While Rex Tillerson, US Secretary of State, said the strike did not mean their wider policy on Syria had changed.
Mr Trump has frequently called for improved relations with Russia which were strained under Mr Obama, but the US president said action had to be taken against Mr Assad.
The US president's surprise missile strike in Syria against the Kremlin's ally has instead thrown down a gauntlet, infuriating Moscow and challenging its dominance in the war-torn country.
As Washington backed off under former president Mr Obama, Mr Putin stepped in to fill the vacuum and reassert Russian influence in the Middle East.
Russia intervened in the conflict on behalf of Mr Assad in late 2015, helping swing the war in his favour.
Russian presence both on the ground in Syria and in the skies complicated any prospect of a no-fly zone which would ground the regime's jets.
Syrian military officials called the US airstrike an act of "blatant aggression", saying it had made America "a partner" of Islamic State of Iraq and the Levant as the base was used to conduct strikes against the jihadist group.
Meanwhile, the Syrian opposition cheered the news, which many said they had been waiting for since the last major chemical attack in 2013.
One senior Syrian rebel official from the Free Syrian Army told the Telegraph he did not want the strikes to be a token gesture however and called for international air strikes against all Syrian air bases.
"We call for there to be joint (international) strikes ... in all the airports" he said. “That’s the only way to protect the people.”