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Former U.S. President Jimmy Carter said Thursday that North Korean leader Kim Jong Il wants direct talks with South Korea's leader — an offer unlikely to be accepted until Pyongyang takes responsibility for violence that killed 50 South Koreans last year.

A summit would be a major step toward smoothing over animosity fueled by the bloodshed, and a personal call from Kim is notable, though North Korea regularly pushes for the resumption of aid-for-nuclear-disarmament talks. It generally wants to return to the negotiating table without preconditions, however.

South Korean President Lee Myung-bak has also floated the possibility of one-on-one talks with Kim — but only if the North takes responsibility for the sinking of a South Korean warship blamed on Pyongyang and an artillery attack on a South Korean island.

Carter told reporters hours after he returned from the North that he and three former European leaders didn't have a hoped-for meeting with Kim during their three-day trip.

But he said that Kim sent them a written personal message as they were leaving, saying he's prepared for a summit meeting with the South Korean president at any time. Carter said North Korean officials expressed deep regret for the deaths on the South Korean warship Cheonan and for the civilians killed in the island shelling.

He added, however, that it was clear that "they will not publicly apologize and admit culpability for the Cheonan incident." North Korea denies sinking the ship, despite a South Korea-led international investigation that blamed the country. It says it was provoked into the island shelling by South Korean live fire drills.

Carter is well-respected in North Korea for his role in helping work out a 1994 nuclear deal that may have averted a war. But officials in Seoul and Washington have put little stock in his ability to engineer a breakthrough this time in nuclear talks.

It has been more than two years since nuclear negotiators from the United States and neighboring nations last met with the North in an effort to persuade it to abandon its atomic weapons programs.

Since then, the North has conducted missile and nuclear tests and proudly unveiled a new nuclear facility that could give it another way to make atomic bombs.

The United States says it won't push forward on nuclear talks until South Korea is satisfied that the North has taken responsibility for last year's violence.

Carter said the goal of his visit is to contribute to greater understanding between North Korea and the outside world, but that it's up to officials to make real progress.

The former American president, former Finnish President Martti Ahtisaari, former Norwegian Prime Minister Gro Brundtland and former Irish President Mary Robinson met with the North's foreign minister and the president of the country's parliament.

When asked why he thought Kim Jong Il did not meet with the group, Carter noted that the South's president did not grant their request for a meeting either.

"We don't question the decision of a head of state about the priorities they set for their own schedule," Carter said.

Carter didn't address the case of Jun Young Su, a Korean-American being held in North Korea, reportedly on charges of carrying out missionary activity. He had said earlier he would not raise the case, though the former president flew to North Korea last year to free another American jailed in Pyongyang.

Carter started Thursday's news conference by offering condolences for those killed in last year's attacks, an apparent nod to criticism that he had glossed over the deaths in past dealings with the North.

But he also likely angered many in Seoul and Washington by criticizing their food aid policies.

Carter said that for the United States and South Korea "to deliberately withhold food aid to the North Korean people because of political or military issues not related is really indeed a human rights violation."

South Korea links aid resumption to progress in ties with North Korea. It says better ties largely depend on Pyongyang taking responsibility for past attacks.

Washington says it's still considering North Korean requests for food, which officials say are evaluated on the basis of need, resources availability and the ability to monitor food distribution.

Years of poor harvests, a lack of investment in agriculture and political isolation have left the North severely vulnerable to starvation.

Former Irish President Robinson said many in the North need help now. She said the country is facing a "matter of utter life and death urgency."