BANGKOK, March 10 -- A Thai navy boat is searching the lower part of the Andaman Sea off southern Thailand in a search and rescue mission following Saturday's reported missing of a Malaysian Airline plane with 239 passengers and crew members aboard.

Thai navy secretary Rear Adm. Kan Dee-ubon said on Monday HTMS Pattani is conducting the search and rescue mission near Langkawi and Perlis islands in the Andaman Sea but found nothing yet.

Navies of several countries in the Southeast Asian region plus those of China and the United States have joined efforts to search the Boeing 777 flight MH 370 which was reported missing after it had taken off from Kuala Lumpur with destination in Beijing.

The Thai navy has prepared a few other patrol boats and aircraft to join the search and rescue mission. HTMS Pattani has not as yet located any flotsam which might possibly be part of the missing airliner, the navy secretary said.

"We're having one boat doing the search and rescue mission in the lower part of the Andaman Sea but we will certainly send for more to join if necessary or requested by the Malaysian authorities," he said.

On stand-by at Pang-nga naval station are HTMS Songkla and a few other patrol boats as well as a Dornier patrol plane.

Though the Andaman Sea was not part of the Malaysia Airline plane's flight path, it is currently under surveillance by the Thai and Malaysian navies because the plane had reportedly changed its course mid-air and might probably have headed back to the Malaysian capital for unknown reasons.

Meanwhile, search and rescue missions are going on in the South China Sea while a Vietnamese navy aircraft spotted a few objects, one looking like a door of an airplane, floating some 50 miles off southwestern Vietnam.

The Malaysian authorities have suspected that international terrorists might possibly have been involved, given the reported uses of fake and invalid passports among the 227 passengers of the missing plane.

Two European nationals who were falsely identified as passengers on the Malaysia Airline flight 370 had reportedly lost their passports while in Thailand while a few others on the plane were believed to have used invalid passports.