BEIJING (Yonhap) -- Envoys from North Korea and the United States held "substantive and serious" talks on Thursday over the North's nuclear weapons program, U.S. chief negotiator Glyn Davies said, announcing an agreement to extend the rare bilateral dialogue by one day.

The Beijing talks, the first since the December death of the North's former leader Kim Jong-il, are widely seen as a chance to gauge whether Pyongyang's new young leader, Kim Jong-un, is open to negotiations to get the communist regime to give up its nuclear ambitions.

Davies told reporters he and his North Korean counterpart Kim Kye-gwan discussed "quite a number of the issues" and plan to hold more talks in the Chinese capital on Friday.

The North's chief envoy Kim also described the Thursday meeting as "positive," saying both sides took part in the talks with a "serious attitude."

Davies said he would hold a dinner meeting with the North Korean delegation.

Before the start of the talks, Davies told reporters, "Today is, as we say, 'Game Day.'" Also on Wednesday, Davies said he saw a "positive sign," but the possibility of resuming six-party talks over the North's nuclear program is up to Pyongyang, reiterating a diplomatic sound bite often used by South Korean and U.S. diplomats

commenting on prospects for the multilateral forum.

The six-party talks, which involve the two Koreas, the United States, China, Japan and Russia, were last held in Beijing in late 2008.

Shortly before the death of Kim, North Korea and the U.S. appeared to be ready to announce a breakthrough that could have led to a resumption of the six-nation talks.

North Korea and the U.S. had been poised to reach a deal in which Pyongyang would halt its uranium enrichment program in return for a resumption of Washington's food assistance.

In Washington, U.S. State Department spokesman Mark Toner described the Beijing meeting as "exploratory talks."

"We've termed them exploratory talks," Toner said. "I think we're going to see how those talks proceed. We're always, I think, cautiously optimistic." Toner said the issue of resuming U.S. food aid to North Korea would be discussed during the Beijing talks.

Last year, diplomatic efforts to get North Korea back to the negotiating table gained some momentum, but the unexpected demise of Kim put a brake on those efforts.

North Korea has not shown any signs of giving up its nuclear programs. The North recently praised its late leader for elevating the country to a nuclear state. North Korea conducted two nuclear tests in 2006 and 2009, drawing international condemnation and tightened U.N. sanctions.

South Korea and the U.S. have insisted the North accept a monitored shutdown of its uranium enrichment program to show sincerity toward denuclearization before reviving the disarmament-for-aid talks.

In 2010, North Korea revealed it was running a uranium enrichment facility. Highly enriched uranium can be used to make weapons, providing Pyongyang with a second way to build nuclear bombs in addition to its existing plutonium program.