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

The meeting, which lasted more than an hour, was "longer than planned, " Russian media quoted Kremlin spokesman Dmitry Peskov as saying.

The two leaders discussed Syria and Ukraine before moving on to a one-on-one talk, Peskov said, noting that the meeting went well.

"Work will continue," the spokesman said.

Meanwhile, U.S. media quoted a senior Obama administration official as saying that the two presidents failed to force a breakthrough in negotiations over a cease-fire for Syria, but have agreed to keep up negotiations.

The two leaders directed their top diplomats to return to talks quickly, likely later this week, the official said.

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.

The G20 summit, which kicked off on Sunday, is set to last through Monday.

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