The United Nations Security Council failed to adopted a Russian-drafted resolution on Saturday that would have condemned "the aggression against the Syrian Arab Republic by the U.S. and its allies in violation of international law and the U.N. Charter."
Only Russia, China and Bolivia voted in favor of the draft resolution. Eight countries voted against the draft, while four abstained. A resolution needs nine votes in favor and no vetoes by Russia, China, France, Britain or the United States to pass.
U.S., British and French forces pounded Syria with more than 100 missiles early on Saturday, in response to a poison gas attack that killed dozens of people last week, in the biggest intervention by Western powers against Syrian President Bashar Assad.
Putin said the U.S. actions in Syria made the humanitarian catastrophe worse and caused pain for civilians.
"Russia in the most serious way condemns the attack on Syria where Russian military servicemen help the legitimate government to fight terrorism," Putin said.
Moscow may consider supplying S-300 surface to-air missile systems to Syria and "other countries", Colonel-General Sergei Rudskoi told a televised briefing on Saturday.
Russia had "refused" supplying those missiles to Syria a few years ago, he added, "taking into account the pressing request of some of our Western partners".
Following the U.S.-led strikes, however, "we consider it possible to return to examination of this issue not only in regard to Syria but to other countries as well," Rudskoi said.
Syria's air defense system, which mostly consists of systems made in the Soviet Union, has intercepted 71 of the missiles fired on Saturday by the U.S., British and French forces, he added.
"In the past year and a half Russia has fully restored Syria's air defense system and continues to further upgrade it," Rudskoi said.