North Korea often threatens to attack the US. The anniversary of the ruling party's founding on Oct. 10 could be used as a stage for a missile or nuclear test.
One benefit of the recent shelling that heightened tensions across the demilitarized zone are the highest level negotiations between Seoul and Pyongyang in many years.
Kim Jong-un's regime gave South Korea 48 hours to stop broadcasting anti-North loudspeaker messages across the demilitarized zone.
Envoys from the US, South Korea, and Japan met Wednesday to discuss ways of curbing North Korea's nuclear ambitions amid concerns of growing instability in the isolated nation.
North Korean defense minister Hyon Yong-chol was killed in front of hundreds of spectators for a variety of offenses, according to South Korea's spy agency. He was the fourth defense minister in 2-1/2 years.
A report in the Wall Street Journal suggests that US defense officials may have underestimated North Korea's nuclear capability.
North Korea's state media praised the knife attack and said it showed anti-US sentiment in South Korea. Ambassador Mark Lippert is recovering after surgery on his face and hand.