North Korea’s military celebrated the controversial nuclear and missile tests

North Korea says it has abandoned the truce that ended the Korean war, amid rising tension in the region.

It blamed its decision on South Korea joining a US-led initiative to search ships for nuclear weapons.

It said the South’s actions were a "declaration of war", and pledged to attack if its ships were stopped.

The move is part of an increasingly hard line being taken by North Korea, and comes two days after it conducted an underground nuclear test.

Meanwhile, South Korean news reports say that steam has been seen coming from a plant at the North’s main nuclear facility, a sign that it has made good on its threat to restart efforts to make weapons-grade plutonium.

The United Nations Security Council is working on a strong resolution condemning North Korea’s actions, including possible punitive measures.