Another North Korean man defected to South Korea on Oct. 30, using a makeshift raft to cross the tense western maritime border, government sources said Tuesday.

A naval patrol ship spotted him some 13 kilometers away from Yeonpyeong Island at around 3:10 a.m. ― about 10 minutes before they found a group of 21 North Koreans on a wooden boat some 41 kilometers west of Daecheong Island.

The two cases are the latest in a series of defections by those who have risked their lives to escape poverty and social and political oppression in the North.

After he left Gangryeong County in Hwanghae Province on Oct. 29, the man on the raft -― fashioned out of planks and tires without an engine ― appeared to have rowed while riding the tidal currents moving southward.

As the county is where North Korea’s coastal military facilities, including launch pads for multiple launch rocket systems, are located, some observers said that he could be a soldier or military civilian worker.

From that county, the North launched its artillery attack on Yeonpyeong Island last November, killing two marines and two civilians.

The defector’s rare use of such a rickety raft to cross the sea border shows how desperate he was to escape the country faltering under international sanctions for its nuclear programs, experts said.

The 21 North Koreans including eight children left Seoncheon County in North Pyongan Province in the late afternoon on Oct. 27. They were found at around 3:20 a.m. by the same South Korean naval ship.

A dog was also found on their 5-ton boat. Seoul authorities are now investigating why they brought the dog despite the high risk of being exposed by its barking in their defection process.

They were mostly fishermen who were disenchanted with the communist regime, according to the sources. They reportedly traded their catches with Chinese, through whom they learned of the advanced South Korean society.

Nearly 22,000 North Koreans are known to have defected here since the Korean War, braving the life-or-death escape.

The annual number of North Korean defectors steadily increased from 2005 until 2009. It was 1,383 in 2005, 2,018 in 2006, 2,544 in 2007, 2,809 in 2008 and 2,927 in 2009, according to the Unification Ministry.

It then slightly decreased to 2,423 last year when crackdowns around the border areas increased as the North stepped up efforts to boost its hereditary power succession scheme.

By Song Sang-ho (sshluck@heraldcorp.com)