However, Thai officials reassured the US Secret Service that lizards found on the Government House grounds were not the dangerous komodo dragons, but water lizards.
Meanwhile, a US explosives team reported five locations Obama will visit during his two-day visit to Thailand have been scanned.
Prime Minister Yingluck Shinawatra’s security detail also was planning and rehearsing for a reception for the US president.
The United States is interested in establishing a humanitarian and disaster relief force at U-Tapao, a naval and air force complex on the eastern seaboard built by the US military during the Vietnam War.
“The return to U-Tapao would be very symbolic for the US, sending a message to China that it is returning to mainland South-East Asia,” said Panitan Wattanayagorn, a military affairs expert at Chulalongkorn University.
Such a move would require approval by Thai lawmakers, some of whom are skeptical about the US military being permanently based in Thailand, he said.
US officials have announced plans to focus more on the Asia Pacific region in military, cultural and development areas.
Meanwhile, US President Barack Obama landed in Thailand on Sunday making him the first sitting US president to set foot in the long-time pariah nation.