White House backs South Korea move to punish North

The White House on Monday gave strong backing to plans by South Korean president Lee Myung-bak to punish North Korea for sinking one of its naval ships.

"We endorse president Lee's demand that North Korea immediately apologize and punish those responsible for the attack, and, most importantly, stop its belligerent and threatening behaviour," White House spokesperson Robert Gibbs said in a statement.

"US support for South Korea's defence is unequivocal, and the president has directed his military commanders to coordinate closely with their Republic of Korea counterparts to ensure readiness and to deter future aggression," he said.