The U.S. team mistook the relatively benign water monitors for the carnivorous komodo dragons as the team conducted security inspections of the Government House Thursday ahead of President Obama's visit that begins Sunday, the Bangkok Post reported.
Meanwhile, a U.S. 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 U.S. 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 U.S. military during the Vietnam War.
"The return to U-Tapao would be very symbolic for the U.S., sending a message to China that it is returning to mainland South-East Asia," Panitan Wattanayagorn, a military affairs expert at Chulalongkorn University, told the Post.
Such a move would require approval by Thai lawmakers, some of whom are skeptical about the U.S. military being permanently based in Thailand, he said.
U.S. officials have announced plans to focus more on the Asia Pacific region in military, cultural and development areas.