Following unsuccessful last-ditch effort by Seoul and Washington to settle differences on their free trade agreement, South Korean President Lee Myung-bak and his U.S. counterpart Barack Obama said Thursday they have decided to give the deal more time.

"We will have to continue negotiations after the G20 summit. It won't take long," Lee told reporters in a joint press conference with Obama, who arrived in Seoul late Wednesday for the G20 summit.

Expectations ran high prior to the talks between Lee and Obama that the two leaders might make a major announcement on the free trade pact.

But a series of talks by top trade officials failed to make breakthrough on the impasse over auto and beef issues.