Blasts heard near North Korea border
North Korea is believed to have fired more artillery shells near the island where four people were killed earlier this week. No shells are said to have landed on South Korean territory.
The firing appears to have been part of a training exercise but came with a warning from Pyongyang that Seoul's plans for military manoeuvres with the US were pushing the region to "the brink of war".
The BBC's Chris Hogg said the firing happened soon after a top American military commander visited the island.