Russian President Vladimir Putin has called the United States airstrikes on Syria an "illegal act of aggression."
According to Putin's spokesman, Dmitry Peskov, the Russian president called the U.S. missile strikes against Syria on April 6 an act of "aggression against a sovereign nation" on a "made-up pretext," the Daily Mail reported.
Putin has now reportedly suspended a deal to avoid mid-air clashes with American fighter jets over Syria, and warned that the missile strikes have done grave damage to Washington and Moscow relations.
"We call upon the UN Security Council to hold an extraordinary meeting to discuss the situation," the foreign ministry in Moscow said in a statement, adding that the strike was a "gross ... violation of international law."
President Donald Trump ordered for 59 Tomahawk missiles to be fired at the al-Shayrat airbase near Homs, according to reports. The strikes killed six people, and destroyed nine Syrian air force planes.
Syrian Army officials called the missile strikes an act of "blatant aggression." They went on to accuse the U.S. of being a "partner" of ISIS, and other "terrorist organizations."
But the U.S. insisted that the military base was used by Syrian President Bashar al-Assad to launch a deadly chemical attack against Syrians that killed 80 people on April 4.
"Assad choked out the lives of helpless men, women and children," Trump said while addressing the nation from his Mar-a-Lago estate, according to NBC. "It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons."
"Years of previous attempts at changing Assad's behaviour have all failed and failed very dramatically," Trump added.
But the Kremlin claimed that Syrian armed forces do not possess chemical weapons. They said this has been confirmed by the Organization for the Prohibition of Chemical Weapons.
"The fact of the destruction of all chemical weapons stockpiles has been recorded and confirmed by the OPCW, a specialized UN unit," Peskov said. "At the same time, in Putin's opinion, total disregard for the use of chemical weapons by terrorists only drastically aggravates the situation."
"Putin also sees the attacks on Syria by the US as an attempt to divert the international community's attention from the numerous casualties among civilians in Iraq," Peskov added. "This move by Washington is causing substantial damage to Russian-US relations, which are in tatters as it is."
Syria's foreign minister, Walid Muallem, has denied allegations that the Syrian government was behind the chemical attack, Al Jazeera reported.
"I stress to you once again: The Syrian army has not, did not, and will not use this kind of weapons -- not just against our own people, but even against the terrorists that are targeting our civilians indiscriminately," he said during a press conference in Damascus.