Military divers plunged into the waters near South Korea’s tense maritime border with North Korea to search for 46 missing marines from a naval ship that sank today, but were hampered by fierce waves and high winds, officials said.

A number of South Korean sailors died today when their navy ship sank after an explosion off an island near North Korea, reports said.

South Korea’s troops went on high alert today for possible retaliation by North Korea after one of its navy ships was nearly destroyed and an officer reportedly killed in a skirmish with the South, ahead of a visit by US President Barack Obama.

NAVY ships from North and South Korea exchanged fire yesterday along their disputed western sea border, the first such clash in seven years.