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South Korea's acceptance of North Korea's offer of high-level defense talks won't solve the rivals' differences overnight: Suspicion is high on both sides, and Seoul still wants an apology for the sinking of one of its warships.

But after months of enmity that had the Koreas trading threats of war, face-to-face talks would be a breakthrough. The new development came just hours after the leaders of the South's ally, the United States, and the North's ally and benefactor, China, jointly urged the Koreas to improve communication.

The Koreas, however, will have to put aside their considerable military and political animosity for any talks to set up a new round of international negotiations on the long-sought U.S. goal of ending North Korea's nuclear programs.

On Friday, Chun Hae-sung, a spokesman for South Korea's Unification Ministry, said North Korea needs to apologize for the March sinking of the South Korean naval ship Cheonan and for the November shelling of South Korea's Yeonpyeong Island, near waters claimed by both countries.

Lower-level defense talks last year went nowhere because of the Cheonan. A South Korean-led international investigation blamed a North Korean torpedo for the sinking, which killed 46 sailors; Pyongyang denies involvement. The North's Nov. 23 artillery attack on Yeonpyeong Island killed two marines and two civilians and infuriated and shocked many in the South.

Chun said the agenda in any talks should include North Korean assurances that it will take "responsible measures" over the Cheonan and the artillery attack and not provoke further conflict.

Last year's attacks and a current North Korean charm offensive pushing for talks come as leader Kim Jong Il looks to prepare his country for a leadership change, apparently to his youngest son Kim Jong Un. The violence might be linked to an attempt by the younger Kim to display his bravery to North Korea's military and bolster his legitimacy as the next leader.

So far, the North has sent encouraging signals on possible talks.

In a letter to South Korea's defense minister, North Korea's defense chief proposed meeting in early February to ease tensions and "express opinions" about last year's two incidents, the North's official Korean Central News Agency reported Friday.

North Korea has taken "a firm stance to resolve" all pending military issues, including the Cheonan sinking and the island shelling, in the high-level talks, KCNA said. "The Korean peninsula is at the crucial crossroads to war or peace," KCNA said.

The North's defense chief also proposed preliminary meetings in late January to discuss details of the high-level talks.

Defense Ministry spokesman Kim Min-seok told reporters in Seoul that preliminary meetings could be held in mid-February.

The South said it will also propose separate talks with North Korea to verify its commitment to abandoning its nuclear programs. South Korea had rejected earlier North Korean calls for unconditional dialogue as insincere.

The two countries' defense chiefs last met in Pyongyang in November 2007, a month after the second summit between the leaders of their countries.

On Wednesday, President Barack Obama and his Chinese counterpart Hu Jintao, meeting in Washington, stressed the importance of an early resumption of six-nation negotiations on North Korea's nuclear programs.

Next week, the United States is sending a senior diplomat, Deputy Secretary of State James Steinberg, to Seoul, Tokyo and Beijing for talks on the Korean standoff.

U.S. State Department spokesman Mark Toner said talks between the Koreas are welcome, "but, obviously, we'd stress that it's important that North Korea continue to take meaningful steps to improve inter-Korean relations."

China also welcomed the agreement to hold talks. "We support and welcome North Korea and South Korea using dialogue to improve relations and bring closer cooperation, and we hope the dialogue has positive results," Foreign Ministry spokesman Hong Lei said in a statement.

Seoul, Washington and Tokyo have pressed the North to prove it is serious about giving up its atomic ambitions before they will allow a new round of aid-for-disarmament talks. North Korea has expressed a desire to restart the nuclear talks it quit in early 2009. The talks involve the two Koreas, Japan, the United States, China and Russia.

North Korea conducted two nuclear tests in recent years and is believed to have produced enough weaponized plutonium for at least half a dozen bombs.

In November, the North showed an American nuclear scientist a uranium enrichment facility that could give it a second way to make atomic bombs. The North said 2,000 recently completed centrifuges were producing low-enriched uranium meant for a new reactor.

Two American nuclear analysts said in a report Thursday that North Korea "appears to have had more success than Iran, and over a shorter time period," in its uranium enrichment program.

David Albright and Paul Brannan, with the Institute for Science and International Security in Washington, wrote that the North's uranium enrichment plant can "be easily used to make weapon-grade uranium for nuclear weapons."

They urged nuclear negotiators to push the North to disable its uranium plant, in addition to focusing on the North's plutonium program. "The new nuclear threat from North Korea is its gas centrifuge uranium enrichment program," the report said.

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Associated Press writers Kim Kwang-tae in Seoul and Cara Anna in Beijing contributed to this report.