Unknown gunmen kidnapped a South Korean trade official in the Libyan capital Tripoli, the foreign ministry in Seoul said today, the latest incident of violence linked to the activities of competing militias.

Western powers fear Libya, an OPEC producer, could slide into further instability as the government struggles to contain heavily-armed militias, tribesmen and Islamists who helped to topple Muammar Gaddafi in 2011 but refuse to disarm.

A foreign ministry official confirmed the identity of the kidnapped man as Han Seok-woo, the head of trade relations at the Korea Trade Investment Promotion Agency (KOTRA).

Four gunmen stopped the car Han was riding in as he was leaving work about at about 5.30 p.m. on Sunday and bundled him into another vehicle, the official said. There was no word from the kidnappers and the reason for the abduction was unknown.

Han, a fluent Arabic speaker and Middle East expert, volunteered for the job and ran the office on the 18th floor of the Tripoli Tower complex with a number of interns, South Korea's Yonhap news agency reported.

His office had been subject to a lockdown last month due to a security dispute, according to the Internet site of KOTRA's Tripoli branch. The foreign ministry issued a travel warning to Libya, following the kidnapping.

South Korea's annual trade volume with Libya stood at $1.8 billion in 2012, the agency's website said, with automobiles making up more than half of its exports to Libya.