U.S. special envoy on North Korea, Stephen Bosworth, and South Korean envoy Wi Sung-lac made no comments after their meeting. Bosworth later met with South Korea's minister in charge of relations with North Korea, and the Unification Ministry said the two agreed to closely cooperate in resolving the nuclear dispute.
Bosworth said in Beijing on Friday that any nuclear development in North Korea was a matter of concern.
"We confirm the necessity to maintain a coordinated position and the need for a complete denuclearization of the Korean peninsula," he said.
Bosworth is to leave for Tokyo on Sunday for similar consultations with Japanese officials. Chief U.S. nuclear negotiator, Sung Kim, plans to return to Seoul on Tuesday to meet with Russian nuclear envoy Grigory Logvinov.
North Korea also announced it is continuing to weaponize plutonium. Uranium offers an easier way to make nuclear weapons, and uranium-based bombs may work without requiring test explosions.
Washington shows no signs of easing pressure on North Korea through new U.N. sanctions, despite a series of conciliatory gestures by the North, including the release of two detained American journalists and a reported invitation to top U.S. envoys, including Bosworth, to visit Pyongyang.
"We are prepared for both dialogue and sanctions," the North said in a letter to the U.N. Security Council carried Friday by its official Korean Central News Agency. If some members of the council put "sanctions first before dialogue, we would respond with bolstering our nuclear deterrence first before we meet them in a dialogue," it said.
The North warned it would be left with no choice but to take "yet another strong self-defensive countermeasure" if the standoff continues. It did not elaborate.
A pro-North Korean newspaper in Japan urged the U.S. to hold talks with the North to make the Korean peninsula nuclear-free. The Choson Sinbo newspaper, widely seen as a mouthpiece for North Korea, said time is not "limitless" for the U.S. to decide whether to hold talks or continue to pursue sanctions.