South Korea has begun live firing drills from a disputed island, despite threats from North Korea.
About two dozen South Korean and US troops, including communications experts and medical personnel, have been deployed on Yeonpyong Island to take part in the artillery drills.
The drills were originally scheduled to be conducted last week but were delayed due to bad weather, providing time for an emergency UN Security Council meeting to try to calm tensions, which ended in disagreement.
South Korea has equipped its F-15K fighter jets and warships with air-to-surface missiles with a range of 278km as well as GPS-guided JDAM missiles to deliver surgical strikes on North Korean artillery positions should they fire.
The live firing drill is expected to create major tensions between the two countries as North Korea had already warned of harder strikes if the drills went ahead.
China and Russia have pressurised Seoul to cancel the exercise, while the US has backed the nation's right to hold the drills.