From left: Austrian Chancellor Christian Kern, Russian President Vladimir Putin, Indian Prime Minister Narendra Modi, Moldovan President Igor Dodon, and NBC's Megyn Kelly. Dmitry Lovetsky/AP Russian President Vladimir Putin cracked some jokes at the West's expense during a key session on Friday at the annual St. Petersburg International Economic Forum, moderated by NBC's Megyn Kelly.

Indian Prime Minister Narendra Modi, Austrian Chancellor Christian Kern, and Moldovan President Igor Dodon appeared on the panel alongside the Russian president.

Asked about the Paris Agreement on climate change that President Donald Trump withdrew the US from on Thursday, Putin replied, "Don't worry, be happy.

"It's about preventing temperature changes of 2 degrees," Putin said, adding that those at the forum "somehow do not yet feel that the temperature is rising. By the way, we should be grateful to President Trump. In Moscow, it's raining and cold and even, they say, some snow. Now, we could blame this all on American imperialism, that it's all their fault, but we won't."

Putin seemed to leave the door open to the US rejoining the agreement, which Trump has said is a possibility.

"The agreement has not yet even come in effect," Putin said. "It will come into effect in 2021. So we still have time. If we all work constructively, we can agree on something."

Kelly later asked Putin about the US intelligence community's assessment that Russian hackers were responsible for the cyberattacks on the Democratic National Committee and Hillary Clinton's campaign chairman, John Podesta, during the 2016 presidential election.

"IP addresses can be invented. A child can do that!" Putin replied. "Your underage daughter could do that. That is not proof." He then compared US intelligence officials blaming Russia for the hacks to "anti-Semitism and blaming the Jews. This is disinformation."

Putin said on Thursday that the Kremlin did not order the hacking campaign, but that "patriotically minded" Russian citizens may have taken it upon themselves to target "those who say bad things about Russia."

When asked at Friday's forum about reports that Russia's ambassador to the US, Sergey Kislyak, met with members of Trump's campaign during the election, Putin was again flippant.

"So our ambassador met someone. So what? It's his job," he said.

He later said Kelly "shouldn't be labeling people" when she asked whether he thought Syrian President Bashar Assad, whom Russia has supported throughout the country's six-year civil war, was "evil."

Putin argued that Assad was not responsible for the chemical attack on the rebel-held town of Khan Sheikhoun in April that killed dozens of civilians, claiming that the massacre was "orchestrated" by Assad's opponents. (Western officials have blamed Assad's military for the aerial gas attack.)

The Russian leader also questioned why Trump was calling on NATO members to increase their military spending, saying the defense organization "was established as a Cold War instrument in the fight against the Soviet Union."

He said there was no longer a Soviet Union, "but NATO is still there."

"The question is, what for?" he said.

Asked whether "squabbles" in the West had helped Russia, Putin said they did if it meant NATO would be dismantled.

Putin and Kelly will sit down for a one-on-one interview on Friday that will air on NBC on Sunday evening.