South Korea warns North after island clash
South Korea says it will retaliate with missile strikes against the North if faced with "further provocations", after an exchange of fire in which two South Korean marines were killed.
President Lee Myung-bak was responding to the shelling of an inhabited island close to a disputed maritime border.
The South returned fire in one of the worst clashes since the Korean War.
US President Barack Obama called the incident an "outrageous, provocative act" by Pyongyang.
The BBC's Damian Grammaticas reports from Seoul.