Mr. Obama said he and Mr. Medvedev agreed to coordinate humanitarian aid to Kyrgyzstan, where about 2,000 people have died in violence after the president was removed from power.

This was the seventh meeting between the two leaders, who will go to Toronto, Canada for the G20 economic summit, which begins Friday.

After their meetings at the White House, Mr. Obama took his Russian visitor to lunch at a hamburger restaurant near Washington. Mr. Medvedev said the beef-and-cheese sandwiches were probably not very healthy, but quite tasty, and part of the spirit of America.