North Korea has said it will sever all ties and communication with Seoul as punishment for blaming the North for the sinking of a South Korean warship two months ago.
North Korea's official Korean Central News Agency said the North will also expel all South Koreans working at a joint industrial park in the border town of Kaesong.
U.S. State Department spokesman Philip Crowley said North Korea's decision to sever ties with the South was an "odd" reaction that works against Pyongyong's self-interest.
Earlier, South Korea resumed
propaganda broadcasts to the North, amid high tension over the sinking of its warship.
An international panel says a torpedo fired from a North Korean submarine sent the ship down in March, killing 46 sailors. Pyongyang denies this.
The North's military says South Korean navy ships repeatedly violated the countries' disputed western sea border this month, and has threatened to take "practical" military measures in response.
Seoul plans to report North Korea to the UN Security Council.
The United States has backed South Korea in the dispute, confirming that it will hold joint naval exercises with the country. China and Russia today called for restraint.compiled from agency reports