SEOUL (KOREA HERALD/ASIA NEWS NETWORK) - A civilian diver taking part in the search for those missing from a recently sunken ferry died on Tuesday after falling unconscious during a mission, officials said.

The diver, identified as a 53-year-old man surnamed Lee, was brought to a hospital in Mokpo, a south-western port city located near the sinking site, around 7.12am local time, but was pronounced dead soon after, Yonhap news agency reported.

Lee, who is a crew member of Undine Marine Industries, lost contact 5 minutes after diving into water around 25 metres deep at 6.05am.

Undine Marine Industries is a private business specialising in offshore and subsea engineering as well as maritime rescue and salvage work.

Local Coast Guard officials said they have suspended all search efforts for the time being following the accident.

Meanwhile, 12 more bodies were retrieved from the sunken ferry on Monday, raising the death toll to 262 and lowering the number of those missing to 40, 19 days after the ship sank off South Korea's southwest coast.