Former US Navy official Robert Kim received a warm welcome from about 100 supporters at Incheon airport, according to Yonhap news agency.

During his stay in South Korea until Feb 14, Mr Kim said he would visit the west coast where more than a million volunteers have worked to clean up the oil spill.

'I heard many people are suffering from the leak of crude oil in waters off Taean and wanted to go there, roll up my sleeves and be of some help,' he was quoted as saying.

Scores of marine farms and miles of beaches along the Yellow Sea coast were fouled when a barge carrying a large crane smashed into a tanker on Dec 7, holing the tanker in three places and spilling 10,900 tonnes of crude.

Two fish farmers and a fish seller have committed suicide following delays by local officials in paying out compensation.

Mr Kim, 67, last visited South Korea in 2005 after a US court ended his probation period.

He emigrated from South Korea to the United States in 1966 and began working as a computer specialist at the US Office of Naval Intelligence in 1978.

Mr Kim was arrested in 1996 for leaking classified information on North Korea to the South Korean embassy in Washington.

He was sentenced in 1997 to nine years in jail and three years on probation but was released in 2004.

The Seoul government denied any direct involvement in the case. But his arrest created sympathy among South Koreans who campaigned to raise funds for him and his family. -- AFP