Senior official Choe Sung-chol was reportedly put to death for accepting bribes.
US envoy Stephen Bosworth is visiting Beijing, Seoul, and Tokyo, after Pyongyang rejected six-party dialogue and threatened to test another nuclear bomb.
United by a common enemy, South Korea's Navy moves to protect a North Korean cargo ship.
Pyongyang may fulfill a vow to conduct another nuclear test, analysts say. It may also be testing US response.
North Korea focused on labor rates in joint industrial complex, while South Korea sought freedom for jailed worker.
A documentary critical of the North, filmed by a family member of one of the journalists, could complicate their case.
The North had announced their expulsion in response to the UN Security Council's condemnation of its missile launch April 5.