North Korea on Saturday stood by its demand for aid in exchange for shutting down a plutonium-producing reactor, insisting that it would not act until Washington offers concessions.

"As we have to follow the `action for action' principle, we will act if action is made," the North's envoy to six-nation disarmament talks, Vice Foreign Minister Kim Gye Gwan, told The Associated Press. "We will never move first."

Kim did not say what concessions the North wanted. He spoke at the Beijing airport as he prepared to return home following the close of the latest round of talks Friday.

The U.S. envoy to the talks, Assistant Secretary of State Christopher Hill, urged the North on Friday to shut down the reactor at Yongbyon but said he had rejected Kim's demand for aid in exchange. Washington says the reactor is producing plutonium, a fuel for bombs.

"They should be stopping their programs immediately," Hill told reporters.

A round of six-nation talks aimed at ending the North's nuclear programs concluded Friday with no sign of progress or a date to meet again.

In response to Hill's call, Kim insisted that Washington lift sanctions on companies accused of weapons proliferation.

There was no indication of progress toward the goal set by host China for this week's talks — agreeing on details of how to carry out North Korea's pledge in September to give up its nuclear program in exchange for aid and a security guarantee.

The competing demands highlight the key dispute in the talks — North Korea's insistence on receiving compensation before it disarms completely, and Washington's refusal to reward Pyongyang until that goal is accomplished.

North Korea also wants a light-water civilian nuclear reactor for power generation before it disarms. But Hill said the other governments agreed that they should not even discuss that until the North's other programs are dismantled.

The talks, the fifth set in a series, began Wednesday and were due to last only three days so diplomats could attend an Asian economic forum in South Korea. The participants are the two Koreas, the United States, China, Japan and Russia.

China issued a brief, upbeat chairman's statement saying negotiators affirmed their September declaration to achieve the "verifiable denuclearization of the Korean Peninsula."

At the talks Hill, repeated Washington's insistence that it would not discuss aid until all the North's programs are dismantled permanently.

"We are not prepared to launch a separate negotiation to have a freeze because freezing programs does not solve this problem," he said. "We have to get rid of these things."

Kim pressed Pyongyang's demand for an end to the U.S. sanctions imposed in October on eight companies accused of trafficking in nuclear, missile or biological weapons technology.

It was unclear whether those sanctions would have any effect, since the United States already bans trade with North Korea. But sanctions also were applied to a Macau bank that dealt with North Korean companies, disrupting Pyongyang's commercial activities.

"These kind of sanctions are in violation of the joint statement we have adopted and are going to hinder the implementation of the commitment we have made," Kim told reporters outside the North's Embassy.

China's statement said negotiators agreed to meet again at the "earliest possible date."

Diplomats said that could be as late as January because of conflicts with other official meetings and the Christmas holiday.

"There was an assessment that it will be a little bit difficult to hold tangible meetings," said the South Korean envoy, Deputy Foreign Minister Song Min-soon.