North Korea's Committee for the Peaceful Reunification of Korea (CPRK), responsible for ties with South Korea, said on Tuesday it would guarantee the businessmen's safety.

BBC: North Korea 'to allow Kaesong managers back'

The second warning in two days came in a statement from the Committee for the Peaceful Reunification of the Fatherland, carried by KCNA news agency.

BBC: North Korea warns South over UN sanctions

It is not clear when or why America abandoned its notion that China should commit itself to peaceful reunification as a precondition for a presidential visit.

ECONOMIST: America and China

Its Committee for the Peaceful Reunification of Korea said the government had no intention of talking with Seoul unless the South abandons its confrontational posture, as the North called it.

NPR: As US Talks Up Diplomacy, NKorea Takes Hard Line

The article quoted the source as saying that Mr Chen's comments "underscore the need for the mainland to proceed with military preparations as a backup to encourage a peaceful reunification".

BBC: Taiwan cancels war games