HONG KONG - Allies and key trading partners expressed disquiet over Thailand's coup Friday, demanding a quick return to civilian rule as some warned against travel to the prime tourist destination.
Japanese auto giants that have invested heavily in Thailand were forced to stop night operations at their factories to comply with a curfew imposed by the new junta, which seized power on Thursday in a move the United States said had "no justification".
Japan, by far Thailand's biggest foreign investor overall, described the coup as "regrettable".
"Our country wants to call strongly for a prompt restoration of a democratic political system," added Chief Cabinet Secretary Yoshihide Suga.
Toyota, the world's number one carmaker which produces 670,000 cars a year in Thailand, said the curfew had halted production at all three of its local assembly plants late Thursday.
Honda Motor also curtailed operations at its plant on Thursday, stopping four hours ahead of its original planned shutdown at midnight, a spokeswoman said.
But the military regime had granted permission to Toyota for Friday's night shift to go ahead, the Japanese firm said.
The Pentagon said it was reviewing military cooperation with America's oldest Asian ally, while Secretary of State John Kerry warned of potential fallout.
"While we value our long friendship with the Thai people, this act will have negative implications for the US-Thai relationship, especially for our relationship with the Thai military," he said.
India's foreign ministry spokesman Syed Akbaruddin also voiced concerns about the situation.
"Some Indian troops who had gone there for joint exercises have been advised to return back to India," he said.
"We hope for an urgent political resolution and restoration of normalcy based on principles of democracy, will of people and rule of law in Thailand." In Beijing, foreign ministry spokesman Hong Lei told reporters: "China and Thailand are friendly neighbours. We hope to see normal social order to be restored as soon as possible in Thailand." The European Union, another of Thailand's top trading partners, expressed "extreme concern" and demanded a rapid return to democracy, while Australia said it was "gravely concerned" at the army's seizure of power.
"It is a volatile situation. We are monitoring it closely but people need to pay close attention to their personal security and their travel plans," Foreign Minister Julie Bishop told ABC radio.