President Vladimir Putin has warned the United States against any unilateral military actions against Syria without approval from the U.N. Security Council, and said Russia would not extradite former intelligence employee Edward Snowden back to the U.S.

"(Approval of any military actions against Syria) must be presented to the UN Security Council if there is evidence that chemical weapons were used and by the government forces," Putin said in an interview with the Channel One TV and the Associated Press, which was published Wednesday ahead of a G20 summit in St. Petersburg.

Putin said Russia would take decisive and serious action over Syria, if clear evidence of the use of mass destruction weapons exists.

He noted that the video footage presented as a proof of chemical attack did not clarify who has gassed these people.

"Who are these people? What has happened to them. There is no answer for that question," Putin said.

He did not rule out that Moscow may give its consent for military operation against Syrian government's targets "if objective, correct data on who has committed these crimes" was available.

"We'll take a principled position that the use of weapons of mass destruction is a crime," Putin said. Otherwise, any use of force against an independent and sovereign state must be qualified as aggression.

"We don't protect that (Syrian) government. We protect norms and principles of international law, modern world order. This is an absolute value," said the president.

Putin noted that Russia supplies Damascus with arms, including some components of S-300 air defense system, to Syria according to previous contracts.

"We cooperate with a legitimate government and don't violate any international norms, nor our obligations," he said, adding that Moscow had suspended delivery of S-300 anti-aircraft systems to Syria.

Meanwhile, Putin confirmed that Moscow did not intend and would not engage in any conflicts in other countries.

"There are no Russian troops abroad ... We are not going to get involved in any conflicts," he said.

Putin also said Russia will not extradite Snowden back to the U.S. as the two countries do not have an agreement on mutual extradition of criminals.

"The problem is not that we defend Snowden. We are not defending him in any way. The problem is that we and the United States do not have an agreement on mutual extradition of criminals," said the president.

"We cannot judge whether Snowden committed some crime in the United States or not... But we, as a sovereign country having no such agreements with the United States, cannot do anything but provide him with the opportunity to stay here," Putin said.

He added that Russia had not received and did not wish to obtain any secret information from Snowden.

Snowden's case was cited by Washington as a reason behind cancellation of U.S. President Barack Obama's planned visit to Moscow.

Putin said he has been upset with that decision but did not consider it a disaster.

"I expect to talk with my U.S. colleague on the G20's sidelines. All our previous meetings were very constructive," Putin said, adding that even a fringe meeting with Obama would be useful.

Among the topics Moscow and Washington have been equally interested in discussing, Putin listed disarmament, global economy, Korean and Iranian issues, and countering terrorism.

"Our disputes stem from different perception of the problems we face, from a different preference of the means to solve them, or perhaps from skills or lack of skills to find compromises and respect a partner's opinion," said the president. Endi