South Korean nuclear negotiators are leaving the door open for direct talks with their North Korean counterparts in New York, where both parties are attending a three-day academic conference.

Lim Sung-nam, South Korea's top envoy to the stalled six-party nuclear disarmament talks with North Korea, told reporters Wednesday that he has no plans for a direct meeting with Pyongyang officials. But he said an impromptu exchange could occur.

Another member of the South Korean delegation, Sohn Hak-kyu, said the two sides planned to meet informally at the conference, which began with a reception late Wednesday.

The forum, hosted by Syracuse University, aims to come up with policy recommendations for ending the standoff between the North and South, which have technically been at war since their conflict in the 1950s.

The conference comes days after North Korea agreed to suspend its uranium enrichment program, stop nuclear and missile tests, and allow inspectors back into its nuclear facilities. The United States agreed at the same time to provide North Korea with at least 240,000 tons of food aid.

Washington has welcomed Pyongyang's move, but said it was only a first step toward the total dismantling of its nuclear weapons programs.

Western observers are closely watching this week's conference for signs of additional concessions by North Korea and its new leader, Kim Jong Un, who took over following the death of his father Kim Jong Il in December.

After arriving in New York Tuesday, North Korea's chief nuclear negotiator, Ri Yong-ho, was quoted by South Korea's Yonhap news agency as saying he was optimistic about the resumption of the six-party talks.

In 2009, North Korea walked out of the negotiations, which also involved South Korea, the U.S., China, Russia and Japan.