NOVO-OGARYOVO, Russia — President Vladimir Putin warned the West against taking one-sided action in Syria but also said Russia “doesn’t exclude” supporting a U.N. resolution on punitive military strikes if it is proved that Damascus used poison gas on its own people.

In a wide-ranging interview with The Associated Press and Russia’s state Channel 1 television, Putin said Moscow has provided some components of the S-300 air defense missile system to Syria but has frozen further shipments. He suggested that Russia may sell the potent missile systems elsewhere if Western nations attack Syria without U.N. Security Council backing.

The interview late Tuesday night at Putin’s country residence outside the Russian capital was the only one he granted prior to the summit of G-20 nations in St. Petersburg, which opens Thursday. The summit was supposed to concentrate on the global economy but now looks likely to be dominated by the international crisis over allegations that the Syrian government used chemical weapons in the country’s civil war.

Putin said he felt sorry that President Barack Obama canceled a one-on-one meeting in Moscow that was supposed to have happened before the summit. But he expressed hope that the two would have serious discussions about Syria and other issues in St. Petersburg.

“We work, we argue about some issues. We are human. Sometimes one of us gets vexed. But I would like to repeat once again that global mutual interests form a good basis for finding a joint solution to our problems.”

The Russian leader, a year into his third term as president, appeared to go out of his way to be conciliatory amid a growing chill in U.S.-Russian relations. The countries have sparred over Syria, the Edward Snowden affair, Russia’s treatment of its opposition and the diminishing scope in Russia for civil society groups that receive funding from the West. And Putin denied that Russia has anti-gay policies, despite a law banning gay propaganda that has caused concern about the country’s role as host of the Winter Olympics in February.

Obama, speaking Wednesday during a trip to Sweden that replaced his Moscow plans, said relations with Russia have “hit a wall,” but also expressed confidence that the two can work together on some issues.

“I have not written off the idea that the United States and Russia are going to continue to have common interests, even as we have some very profound differences on some other issues,” he said, noting that those differences include Syria.

Putin said it was “ludicrous” that the government of Syrian President Bashar Assad — a staunch ally of Russia — would use chemical weapons at a time when it was holding sway against the rebels.