North Korea threatens pre-emptive strike over sanctions

North Korea has announced it has scrapped all of its peace pacts with South Korea, cutting off the hotline between the nations' capital cities.

The move follows a fresh round of UN sanctions punishing Pyongyang for its nuclear test last month.

China, North Korea's only ally, has appealed for calm and said both sides should continue talks to avoid "further escalation".

Lucy Williamson reports from Seoul in South Korea.