HANGZHOU, Sept. 5 (Xinhua) -- U.S. President Barack Obama and his Russian counterpart, Vladimir Putin, met here Monday on the sidelines of the 11th Group of 20 summit to discuss the Syria and Ukraine issues.

The two presidents talked for more than one hour, longer than planned, and discussed Syria and Ukraine issues, Russian media quoted a Kremlin spokesman as saying.

The United States and Russia have been trying to reach a deal over the Syria crisis. Obama said Sunday that the two sides still have "grave differences," but there is still possibility "to make some progress."

U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov, who met in this eastern Chinese city on Sunday for Syria talks, launched a fresh round of negotiations on Monday morning, but ended without agreement, U.S. media reported.