Asked to let Americans in on a secret about White House life, the president chose the pastry chef and rued that "the best pie I have ever tasted" is a challenge to the first couple's self-discipline and waistlines. Asked to choose between basketball greats Kobe Bryant and Michael Jordan, Obama — a committed hoops player and fan of Jordan's Chicago Bulls — didn't pause for even a second. "Michael," he said, picking the retired superstar. "I haven't seen anybody match up with Jordan yet."

Scheduled to depart Sunday for a trip to Russia, an international summit in Italy and his first trip to Africa as president, Obama praised Moscow for its cooperation in international efforts to persuade North Korea and Iran to abandon their nuclear development programs. After North Korea conducted an underground nuclear test in May, the United Nations approved "the most robust sanction regime that we've ever seen with respect to North Korea," he said.

He expressed optimism he could get international agreement for even tougher action if North Korea persists in defying demands that it dismantle its nuclear weapons and stop production. The U.N. sanctions, for instance, did not include one thing the U.S. wanted: allowing the use of military force to board and inspect ships suspected of carrying banned weapons.

"In international diplomacy, people tend to want to go in stages," Obama said. "There potentially is room for more later."

The main agenda item for Obama and Russian President Medvedev in Moscow is to advance talks on a new strategic arms reduction treaty to replace one that expires in December.

In addition to sitting down with Medvedev, Obama also is meeting with Putin, the former president who now is prime minister but still a major force.

"I think that it's important that even as we move forward with President Medvedev that Putin understand that the old Cold War approaches to U.S.-Russian relations is outdated — that's it's time to move forward in a different direction," Obama said.

He said Medvedev understands that, but Putin needs convincing that the U.S. wants cooperation rather than "an antagonistic relationship."

On Afghanistan, Obama said he intends to reassess the possible need for additional U.S. troops after the nation holds national elections in August, but that he believes America's key goals can be met there "without us increasing our troop levels."

He has ordered 21,000 more troops to Afghanistan this summer, bringing the U.S. total to 68,000. He spoke on a day when 4,000 of those newly arrived Marines stormed through southern Afghanistan and when news surfaced that an American soldier who disappeared after walking off his base in eastern Afghanistan was believed captured.