朝鲜不准韩国工人进入开城工业园区

North Korea is blocking entry of South Korean workers into a joint industrial zone just north of the border, jeopardizing the last remaining sign of cooperation between the two foes.

Pyongyang announced Wednesday it is suspending South Korean access to the
Kaesong industrial complex, but said it would allow the South Korean workers
at the facility to leave.

South Korea says it was not told how long the entry ban will last, but warns that, if it is prolonged, South Korean workers could run out of supplies and food. Unification Ministry spokesperson says the safety of its workers is Seoul's top priority.

Seoul's defense ministry says that military action is a last-resort option if the safety of the workers is threatened.

Pyongyang has previously blocked South Koreans from entering or exiting the complex, which opened in 2004. But this appears to be the most serious threat yet to the center, which provides about $2 billion a year in trade for the impoverished North.

South Koreans who work in Kaesong are expressing concern about their safety.

The move came just hours after U.S. Secretary of State John Kerry warned Pyongyang against making further provocative threats against Washington and its allies.