Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. US Secretary of State in Seoul for Talks on Tensions Between North, South VOA News 26 May 2010 South Korean activists and North Korean defectors shout slogans during a rally against the North near the National Assembly in Seoul, South Korea, 25 May 2010 Photo: AP South Korean activists and North Korean defectors shout slogans during a rally against the North near the National Assembly in Seoul, South Korea, 25 May 2010 U.S. Secretary of State Hillary Clinton has arrived in Seoul, one day after Pyongyang vowed to sever all relations with its neighbor in a dispute about the sinking of a South Korean warship. North Korea said early Wednesday that it had shut down its maritime communications links with South Korea, following Tuesday's announcement that it will have no ties with Seoul while South Korean President Lee Myung-bak is in office. Mr. Lee has taken a harder line with North Korea than other recent South Korean presidents. The regime also announced it would block road traffic to a joint industrial estate across the heavily armed border if South Korea resumes propaganda broadcasts to the North. South Korea says a North Korean torpedo sank the South Korean warship Cheonan in March, killing 46 sailors. Officials in Seoul say they plan to take the matter to the United Nations Security Council. South Korea said Monday it is implementing its own sanctions against the North in retaliation for the torpedo attack. North Korea denies responsibility for the incident. Seoul announced Tuesday that it will employ 10 warships in an anti-submarine drill Thursday in the waters off the Korean peninsula. The U.S. said it plans joint military exercises with South Korea in the near future. For its part, North Korea also vowed to expel all South Korean officials from an inter-Korean industrial complex in the North Korean border town of Kaesong. Other steps announced include banning South Korean ships and airliners from passing through its territory, and a resumption of psychological warfare against the South. U.S. State Department spokesman PJ Crowley said Tuesday that North Korea's decision to cut ties with the South was contrary to Pyongyang's long-term interests. Crowley said North Korea is not able to feed its people while South Korea has one of the world's most dynamic economies. Some information for this report was provided by AFP, AP and Reuters. .