MOSCOW - Russia on Friday condemned the U.S. missile strike against Syrian government forces as an attack against its ally, and said it was pulling out of an agreement to minimize the risk of in-flight incidents between U.S. and Russian aircraft operating over Syria.
Even as Russian officials expressed hope that the U.S. strike against Bashad Assad would not lead to an irreversible breakdown in relations with Moscow, the Kremlin's decision to suspend the 2015 memorandum of understanding on the air operations immediately raised tensions in the skies over Syria.
President Vladimir Putin's spokesman said the risk of confrontation between aerial assets of the U.S.-led coalition and Russia has ''significantly increased'' after President Trump ordered the launch 59 Tomahawk cruise missiles at a Syrian military air base in retaliation for a chemical attack that killed scores of civilians.
The now-scrapped pact traded information about flights by a U.S.-led coalition targeting the Islamic State and Russian planes operating in Syria backing the Assad government.
The Russian spokesman, Dmitry Peskov, further claimed that the Syrian government had no chemical weapons, and dismissed the Trump administration's explanation as an excuse to enter the conflict.
''President Putin considers the American strikes against Syria an aggression against a sovereign government in violations of the norms of international law, and under a far-fetched pretext,'' Peskov told reporters. ''This step by Washington is causing significant damage to Russian-American relations, which are already in a deplorable state.''
''Of course, Syria is our ally, considering that we are helping the Syrian armed forces at the Syrian leadership's request,'' Peskov said.
The strike creates the possibility of a direct confrontation with Russia, which has forces on the ground and advanced air-defense systems capable of shooting down U.S. aircraft and missiles.
The 2015 agreement details steps Russian and U.S.-led coalition pilots should take to avoid accidental encounters as they carry out strikes against separate targets.
It was also intended to head off the possibility of Russian air defenses shooting down U.S. aircraft, drones or missiles. Russia's foreign ministry spokeswoman, Maria Zakharova, said Friday that Moscow ''will never agree to attacks on the legitimate authorities'' in Syria.
''We see these actions taken by the American side as a grave violation of the memorandum,'' Russian Defense Ministry spokesman Igor Konashenkov told reporters on Friday.
Russia, he added, would help strengthen Syrian air defenses to ''protect the most sensitive Syrian infrastructure facilities.''
There have been no reports of Russian casualties in Friday's strike, but Syria officials claimed there were civilian casualties, including children.
A Pentagon spokesman, Capt. Jeff Davis, said in a statement that ''U.S. military planners took precautions to minimize risk to Russian or Syrian personnel located at the airfield.''
Zakharova, the Foreign Ministry spokeswoman, also dismissed the U.S. assertion that the attacks were a response to this week's chemical weapon attack in northern Syria, which left scores dead in a village in Idlib province - one of the last strongholds of anti-Assad factions.
''It is obvious that the strike by U.S. cruise missiles was prepared well in advance,'' Zakharova said on Russian state television. ''It is clear to any specialist that the decision to deliver the strikes was made in Washington before the Idlib events, which were simply used as a pretext for demonstrating force.''
Putin's spokesman said the Russian president considered the attack an attempt to distract attention from the heavy civilian casualties caused by the U.S.-backed offensive to capture Mosul, Iraq from the Islamic State group.
Trump speaks on missile strike he ordered against Syria
Trump speaks on missile strike he ordered against Syria
''This step is not taking us any closer to the final goal in the fight against international terrorism, but, on the contrary, it is creating a serious obstacle to the establishment of an international coalition to combat it and efficiently counter this global evil,'' Peskov said.
Under a 2013 Russia-U. S. agreement, Syria agreed to dismantle its chemical weapons stockpile. A U.N. mission in 2014 confirmed that most of Assad's ''declared'' chemical arsenal had been eliminated. But this week's attack in Idlib raised questions about whether some arms were held back.
Secretary of State Rex Tillerson, who is due to arrive in Moscow next week, said the attack on Idlib meant that ''clearly, Russia has failed in its responsibility to deliver on that commitment,'' told a briefing late Thursday.
''So either Russia has been complicit or Russia has been incompetent in its ability to deliver on that agreement,'' Tillerson said.
Other Russian officials issued grave condemnations of the U.S. strike.
''This is fraught with the possibility of a clash between Russia and the USA, and the consequences might could be the most severe, including military conflict,'' Mikhail Yemelyanov, a member of the lower house of the Russian parliament, told the Interfax news agency. ''Here you can't rule out anything.''
''This will have negative consequences for normalization of the situation in Syria,'' said Viktor Ozerov, the head of the defense and security committee of the upper house of the Russian parliament.
He said the attacks would give the wrong signal to Assad's opposition, and undermine the peace process.
Peskov had told the Associated Press on Thursday that Russia's support for Assad was not unconditional, but insisted that Russia wants to see a full investigation into the use of chemical weapons in Syria before the United Nations takes any action.
Putin carefully orchestrated a peace process that brought together Turkey and Iran - regional powers that have backed opposing sides in the civil war. At the same time, the chemical weapons attack suggests that Assad and his Iranian allies had no intention of being party to a power-sharing agreement, suggesting that Putin's deal is all but dead.
Russian-American relations are at their lowest point in decade, over Moscow's annexation of Crimea and its proxy war in eastern Ukraine, as well as allegations that the Kremlin interfered in the U.S. presidential election.
Following the election of Trump, Russian leaders expressed measured optimism for an improvement in relations, but Peskov and others have said that so far there has been minimal dialogue. Trump did call Putin on Monday to express condolences after an explosion Russian investigators have called a terrorist attack killed 14 and wounded dozens more in a St. Petersburg subway train.