A South Korean reconnaissance plane inadvertently dropped anti-ship missiles into the sea after the aircraft crew accidentally activated the missile release mechanism. Officials said the incident did not cause any damage.

The P-3CK maritime surveillance aircraft, operated by the South Korean navy, was on a routine reconnaissance mission over the East Sea, also known as the Sea of Japan. The four-engine plane's crew had erroneously pressed a button releasing three Harpoon missiles, a torpedo and other weapons into the sea.

None of the weapons was armed when they hit the waters. "One of the plane's crew mistakenly touched the emergency weapons release switch at around 6.10am [local time]. There was one fishing boat in the area but it sustained no damage," an official source told South Korea's Yonhap news agency.

The South Korean navy said a mine sweeper and a recovery vessel have been deployed to collect the submerged weapons. The incident occurred at about 30 miles east of the country South Korean north-eastern county, Yangyang. Routine inspections are to continue in the region by the aircraft as mechanical glitches were discovered.