Vladmir Putin under pressure to change stance on Syria

Vladimir Putin has warned the U.S. about launching military action in Syria, saying that Russia has "plans" on how it would react in such a scenario.

Putin's comments come as President Barack Obama announced his plans for military action as part of a broader strategy to topple Syrian President Bashar al-Assad.

Putin said that it was too early to talk about what Russia will do should the U.S. attack Syria.

At the same time, he said Russia did not exclude supporting a UN resolution on military strikes should it be proven that Damascus used poison gas on its own people.

The suggestion that Russia might support a resolution on strikes is unlikely to be taken seriously in the United States, as Putin has made comments on the situation repeatedly.

Russia has previously protected Syria from punitive action using its veto at the UN Security Council.

Putin will be confronted at the G20 summit this week about French evidence linking Syrian government forces with a massive, coordinated chemical attack on August 21, which left hundreds of civilians dead. The evidence includes documentation and satellite imagery showing the attacks coming from government-controlled areas toward rebel-held zones.

Russian foreign minister Sergey Lavrov rejected previous Western intelligence as unconvincing and without proof. But Putin, as host of the G20, will face a challenge Thursday and Friday at the summit both to accept the intelligence and propose a diplomatic solution, potentially by limiting his support for Assad.