SAN JOSÉ DEL CABO, Mexico — President Vladimir V. Putin of Russia said Tuesday that the fate of President Bashar al-Assad of Syria should be left to the hands of the Syrians, saying that no one country has the right to tell another people whom their leader should be.

Appearing at a freewheeling news conference here at the close of the Group of 20 summit meeting of world leaders, Mr. Putin expounded on a range of issues. He discussed the London Olympics (he plans to attend and said he was excited about watching the judo matches) as well as the agenda next year when Russia hosts the Group of 20 economic conference in St. Petersburg (he said he was worried about the strength of the United States dollar and America’s debt).

His handlers seemed to try to end the news conference several times, but a smirking Mr. Putin would extend it for “one more question.”

With a grin, he said, “Let’s not look like we are so professionally organized.” He appeared to enjoy the give-and-take with the reporters, some of whom cheered for him at the news conference’s close.

He was asked if he had made the case to President Obama during their meeting the day before that Congress should hurry up and grant trade benefits to Russia now that Moscow has acceded to the World Trade Organization. “I didn’t make any case,” he replied. “What case do I need to make? If the Congress decides to adopt this new law, that’s up to them.”

He said that for Russia, “U.S. trade is peanuts,” but he warned that the Kremlin would retaliate and bar trade benefits to American companies if Congress did something similar to Russia.

One reporter asked Mr. Putin, a former K.G.B. colonel, with whom he would most like to take on a spy mission.

“With nobody,” Mr. Putin said. “I’m not a spy anymore.” (Copyright 2012 The New York Times Company 06/20/12)