U.S. President Barack Obama confirmed on Tuesday, Aug 6, that he would go to Russia this fall for a G20 summit but said he was "disappointed" that Russia granted temporary asylum to former U.S. spy agency contractor Edward Snowden, Reuters reported.

Speaking on NBC's "The Tonight Show" with host Jay Leno, Obama said Moscow sometimes slipped into a Cold War mentality, despite being cooperative with the United States on some issues, including counterterrorism efforts in the aftermath of the Boston Marathon bombing.

Obama was not asked and did not mention whether he would attend a separate meeting with Russian President Vladimir Putin during his Russian trip. That meeting was put in question after Moscow rejected U.S. pleas and granted Snowden a year's asylum. The White House has said it is evaluating whether a one-on-one with Putin makes sense.

"There have been times where they slip back into Cold War thinking and a Cold War mentality," Obama said of Russia. "What I say to President Putin is, that's the past and ... we've got to think about the future. And there's no reason why we shouldn't be able to cooperate more effectively than we do."

During the interview, Obama also said the recent threat that caused the United States to close its embassies throughout the Middle East was significant.

"It's significant enough that we're taking every precaution," Obama said. "It's a reminder that for all the progress we've made ... this radical, violent extremism is still out there," Obama said. "We've got to stay on top of it."