SEOUL, Aug 30, 2008 (AFP) - South Korea on Saturday urged its nationals to avoid travelling to Thailand, citing the ongoing political unrest in the Southeast Asian country.

"Korean citizens should stay away from any sites of demonstration and others who plan to travel to Thailand should wait until calm returns," the foreign ministry said in a statement.

The ministry also sent an emergency mobile phone text message to South Koreans travelling in Thailand and put up warnings on its Internet homepage to that effect, it said.

Hundreds of South Koreans have been stranded on the holiday isle of Phuket since Thailand's second-busiest airport was closed Friday afternoon, South Korean diplomats said.

Thai officials said about 15,000 passengers were stranded in Phuket on Saturday as hundreds of anti-government protesters blocked access to the airport.