NEW YORK - Representatives from the United States and the Democratic People's Republic of Korea (DPRK) Thursday concluded their first day of a two-day dialogue aiming at reviving the long-stalled six-party talks on the denuclearization of the Korean Peninsula, with the US side describing the discussion as "serious and business-like."

DPRK Vice Foreign Minister Kim Kye-Gwan left the US Mission to the United Nations building, where the bilateral talk was taking place, about an hour earlier than originally scheduled, without making any comments to reporters.

While the US State Department released a brief readout, calling the first-day discussions "have been serious and business- like."

"We look forward to continuing our meetings tomorrow," said the readout.

It added that this is "an exploratory meeting" to determine if DPRK is prepared to fulfill its commitments under the 2005 Joint Statement of the six-party talks and its international obligations, as well as to take concrete and irreversible steps toward denuclearization.

"We continue to coordinate closely with the Republic of Korea(ROK) and our other partners," it said.

Also on Thursday, US State Department spokesperson Mark Toner told reporters in Washington that the New York talks are "a chance for us to sound out the North Koreans" and "gauge their seriousness."

"Words are not enough," Toner told a Washington briefing. "We need action."

According to ROK's Yonhap News Agency, Kim told reporters after landing in New York Tuesday that he was " optimistic" the six-party talks could resume and that relations with the US might improve.

"Now it's the time for countries to reconcile," he said.

The bilateral talks came after US Secretary of State Hillary Clinton on Sunday invited Kim to New York for talks on the potential resumption of the six-party talks, which has been on hold since December 2008.

Last Friday, ROK's chief nuclear envoy Wi Sung-lac and his DPRK counterpart Ri Yong-ho held a bilateral meeting in Bali, Indonesia, during which the two sides agreed to work to resume the six-party talks, which also includes China, Russia and Japan.