BISHKEK, Krgyzstan — Russian President Vladimir Putin on Friday welcomed Syria's announcement that it had joined a global anti-chemical weapons treaty, saying it showed Damascus was serious in its intention to resolve conflict in the country.

Syria became a full member of the global anti-chemical weapons treaty on Thursday, the country's U.N. envoy said, a move that the government of Syrian President Bashar Assad had promised as part of a Russian plan to avoid U.S. strikes.

"I believe we should welcome such a decision," Putin told a Shanghai Cooperation Organisation summit." [It] is an important step towards the resolution of the Syrian crisis, this confirms the serious intention of our Syrian partners to follow this path."

Syria agreed to the plan brokered by Russia, its most powerful ally, to transfer its chemical arms to international custody after Washington threatened military strikes over a gas attack on Aug. 21 that it attributes to government forces.

China's President Xi Jinping threw his weight behind the Russian initiative and the Chinese Foreign Ministry said in an a statement released almost simultaneously that it welcomed Damascus's move to join the anti-chemical arms convention.

Both Russia and China have blocked successive U.N. Security Council resolutions aimed at pressuring Assad to end violence that has killed more than 100,000 in the more than two-and-a-half year-long conflict.