<\/a>North Korea blocked South Koreans on Wednesday from crossing the heavily armed border to a jointly-operated industrial park, raising doubt about the future of the last remaining major symbol of inter-Korean cooperation.<\/span><\/p>\n <\/span><\/p>\n The move came four days after North Korea threatened to shut down the industrial park, in the North Korean town of Kaesong, out of anger over United Nations sanctions and joint military drills that the United States and South Korea are conducting on the Korean Peninsula.<\/span><\/p>\n <\/span><\/p>\n More than 480 South Koreans \u2014 many with their trucks \u2014 who showed up at a border crossing Wednesday morning were denied permission to cross and had to turn around, said the Unification Ministry of South Korea, which is in charge of relations with the North. But North Korea promised to allow 861 South Koreans currently staying in Kaesong to return home if they wished, the ministry said. But with no replacements arriving, only 33 decided to return home on Wednesday.<\/span><\/p>\n <\/span><\/p>\n Officials feared that if the one-way blockade continued, it would asphyxiate the eight-year-old industrial park, which produced $470 million worth of goods last year, helping provide a badly needed source of cash for the North, which faces heavy global sanctions.<\/span><\/p>\n <\/span><\/p>\n The complex, on the western edge of the border of the two Koreas, generates more than $92 million a year in wages for 53,400 North Koreans employed by 123 textile and other labor-intensive South Korean factories there.<\/span><\/p>\n <\/span><\/p>\n Its fate has been seen as one indicator of how far North Korea may be willing to take its recent threats against South Korea and the United States, with the site\u2019s continued operation considered one of several signs that North Korea was not going to match its tough talk with actions.<\/span><\/p>\n <\/span><\/p>\n \u201cIf this doesn\u2019t end in a day or two, it will cause us a serious trouble because we have orders to meet,\u201d said Bang Bok-jin, an official at Jaeyoung Solutec Co., which employs 1,000 North Koreans in Kaesong assembling tiny cameras for smart phones and rear-view mirror modules for cars.<\/span><\/p>\n <\/span><\/p>\n Mr. Bang said in a telephone interview that there was nothing unusual in Kaesong and along the border crossing when he visited the park on Tuesday, except that North Korean soldiers wore tree branches as camouflage, apparently as part of their ongoing military exercise. After he was denied entry, Mr. Bang was waiting at the border crossing on Wednesday to see if returning colleagues could bring out goods to meet the most urgent orders.<\/span><\/p>\n <\/span><\/p>\n \u201cThis is a very regrettable situation,\u201d said Kim Hyung-suk, spokesman of the Unification Ministry, calling for the North to immediately normalize cross-border traffic. \u201cTo encourage the investment North Korea says it wants, it must above all build mutual trust with South Korea and the international community and make itself predictable.\u201d<\/span><\/p>\n <\/span><\/p>\n It was not the first time that North Korea had disrupted the park\u2019s operation. It blocked cross-border traffic three times in 2009, once for three days, out of anger over joint military drills by South Korean and American troops.<\/span><\/p>\n <\/span><\/p>\n That blockade was lifted when the military exercises ended. The current U.S.-South Korean military drills are to continue until the end of April.<\/span><\/p>\n <\/span><\/p>\n Wednesday\u2019s blockade came a day after North Korea announced plans to restart a reactor at its main nuclear plant in Yongbyon, a step that would revive its ability to produce plutonium for nuclear weapons<\/a>, and it also said it would use a uranium-enrichment plant on the site for its weapons program.<\/span><\/p>\n <\/span><\/p>\n China\u2019s deputy foreign minister, Zhang Yesui, met with the ambassadors of the two Koreas and the United States on Tuesday to express serious concern over the situation on the Korean Peninsula, Hong Lei, a spokesman of the Chinese Foreign Ministry, said on Wednesday.<\/span><\/p>\n <\/span><\/p>\n \u201cThe improvement of relationships between the two Koreas, as well as their reconciliation and cooperation, are conducive to the peace and stability on the peninsula,\u201d he said. \u201cWe hope the two Koreas could resolve the relevant issues through dialogue and consultation.\u201d<\/span><\/p>\n <\/span><\/p>\n As the North Korean nuclear crisis unfolds, the United States was dealing with another delicate nuclear issue involving the Korean peninsula: South Korea\u2019s request for the right to enrich uranium to fuel its fast-growing nuclear power industry. South Korea is concerned about its fast-growing stockpiles of nuclear waste, and wants to reprocess the spent fuel to relieve the problem.<\/span><\/p>\n <\/span><\/p>\n But the same processes can be converted to make nuclear weapons. Although South Korea has repeatedly denied any intention of making bombs, negotiations between Seoul and Washington over the issue have stalled for years, with the United States intent on preventing the spread of such technologies.<\/span><\/p>\n <\/span><\/p>\n President Park Geun-hye of South Korea, the leader of a country ambitious to become a major global player in nuclear energy<\/a>, has been pressing for a compromise ahead of her planned trip to Washington in May, a sentiment echoed by American officials.<\/span><\/p>\n <\/span><\/p>\n \u201cWe\u2019ve exchanged some ideas, and I will follow up on those when I visit Seoul in about a week,\u201d Secretary of State John Kerry said, adding that he hoped that an agreement can be reached before President Park\u2019s visit.<\/span><\/p>\n <\/span><\/p>\n While American officials played down any immediate threat from Pyongyang, they still worry about the consequences of any miscalculation, given the hair-trigger tensions on the Korean Peninsula and Mr. Kim\u2019s inexperience at this type of brinkmanship.<\/span><\/p>\n <\/span><\/p>\n The top American commander in South Korea, Gen. James D. Thurman, called the situation \u201ctense\u201d and \u201cvolatile\u201d in an interview Tuesday with ABC News.<\/span><\/p>\n <\/span><\/p>\n But a senior American official predicted that North Korea would eventually back down, as Mr. Kim\u2019s need for food aid<\/a> and hard currency outweighed the domestic political gains from his threats to shoot missiles at American cities.<\/span><\/p>\n <\/span><\/p>\n \u201cThe North Koreans want the international community to feed their people, fuel their factories and fill their bank accounts,\u201d the official said. \u201cIf North Korea were a self-sufficient enterprise, we would have a much bigger problem on our hands.\u201d<\/span><\/p>\n