UN Secretary-General Ban Ki-moon has warned the crisis on the Korean peninsula may become "uncontrollable," BBC News reported.

He once again urged North Korea to tone down its "provocative rhetoric" and to keep open a joint North-South Korean industrial complex.

Also on Tuesday, April 9 North Korea warned foreigners in South Korea to take evacuation measures in case of war. Pyongyang has been making bellicose threats against South Korea, Japan and US bases in the region.

Speaking to reporters in Rome, Ban said: "If any small incident is caused by miscalculation or misjudgement, it may create an uncontrollable situation.''

He also called for the Kaesong Industrial Complex to be kept open, calling it "one of the most successful cooperative projects between the South and North".

"This should not be affected by political considerations. This is a purely economic place," he went on.