Korea must guarantee the safe return of our personnel and fully protect the assets of the companies with investment in Kaesong," he added.

He did not give a timescale for the withdrawal. A total of 175 South Korean workers are currently in the complex, which is home to South Korean factories staffed by North Korean workers.

Timeline: Korean tensions 12 Dec: North launches a rocket, claiming to have put a satellite into orbit

North launches a rocket, claiming to have put a satellite into orbit 12 Feb: North conducts underground nuclear test

North conducts underground nuclear test 11 Mar : US-South Korea annual military drills begin

: US-South Korea annual military drills begin 30 Mar: North says it is entering a "state of war" with South

North says it is entering a "state ofwar" with South 2 Apr: North says it is restarting Yongbyon reactor

North says it is restarting Yongbyon reactor 3 Apr: North blocks South workers from Kaesong industrial zone

North blocks South workers from Kaesong industrial zone 9 Apr: North pulls its workers from Kaesong zone

North pulls its workers from Kaesong zone 10 Apr: North moves two mid-range Musudan missiles to its east coast

North moves two mid-range Musudan missiles to its east coast 26 Apr: South Korea announces withdrawal of all remaining South Korean workers Q&A: Kaesong Industrial Complex Analysis: The North Korea threat Missile defences in the region Picking apart the bluster

The remaining South Koreans were believed to be running out of food and medicines, because the North had refused to allow fresh supplies in.

But an association representing the