North Korea's envoy to the United Nations said Tuesday his nation is willing to conduct parallel talks on its nuclear program and on formally ending the Korean War, but only if all sanctions against it are lifted.

Summoning a few reporters to North Korea's U.N. Mission, Ambassador Sin Son Ho described U.S. and international sanctions as "an expression of distrust" that must be put aside before the North will rejoin stalled six-party talks to rein in its nuclear program and rid the Korean Peninsula of nuclear weapons. The talks have involved the two Koreas, China, Japan, Russia and the United States.

He repeated his country's position, outlined in a statement Monday from North Korea's Foreign Ministry, that it will only resume the nuclear talks and start peace negotiations to formally end the Korean War after international sanctions on it are lifted.

Asked about the timing of resuming the six-party talks and peace negotiations with the U.S., Sin said, "we can work in parallel."

"The six-party talks is possible to be returned to sooner ... if the sanctions are removed," Sin said during a question-and-answer session. "Sanctions itself is an expression of distrust.

"A cease-fire agreement should have been signed long ago already," he said. "We will try to push the U.S."

But the U.S. and South Korea have already rejected the North Korean proposal outlined Monday.

Seoul said Tuesday that sanctions can be lifted only after the North rejoins disarmament talks and reports progress in denuclearization.

U.S. State Department spokesman P.J. Crowley on Monday urged Pyongyang to return to the talks, "and then we can begin to march down the list of issues that we have."

Despite the rejections, the North's top diplomat in Beijing on Tuesday repeated his country's position that it will only resume the nuclear talks after international sanctions on it are lifted.

"If sanctions are lifted, the six-party talks can be held at once," North Korean Ambassador to China Choe Jin Su said in a group interview in Beijing, according to Japan's Kyodo News agency.

The U.N. Security Council imposed tough new sanctions on North Korea last June, strengthening an arms embargo and authorizing ship searches on the high seas. Those were intended to rein in its nuclear program after Pyongyang's second nuclear test last May, which violated a council resolution adopted after its first nuclear blast in 2006.

Choe also said the conclusion of a peace treaty will help promote denuclearization "at a rapid tempo," Kyodo reported.

North Korea, which claims it was forced to develop atomic bombs to cope with U.S. threats, called for a peace treaty to be concluded this year, which it emphasized marks the 60th anniversary since the outbreak of the Korean War.

The signing of a peace treaty has been discussed at the six-nation disarmament talks before but has always been based on the assumption that there would be progress in North Korea's denuclearization.

The North quit disarmament talks last year in anger over international condemnation of a long-range rocket launch. The country later conducted its second nuclear test, test-launched a series of ballistic missiles and restarted its plutonium-producing facility, inviting widespread condemnation and tighter U.N. sanctions.