The Japanese and US embassies in Bangkok have urged their citizens in Thailand to be alert for a possible terrorist attack.



Both missions issued security warnings on Thursday, after reports said about 40 Uyghurs were forcibly returned to China from immigration detention in Thailand.



Japan said places where large numbers of people gather could become targets of terrorism. The government urged Japanese nationals to remain vigilant and keep updated on the latest safety advisories.



The US called on Americans to show caution and review their personal security plans.



More than 300 Uyghurs were placed in custody in Thailand in 2014 on suspicion of illegal entry into the country. Forty-eight had remained in detention since then.



Thailand confirmed the transfer of the Uyghurs. The country's prime minister said Friday she's confident China will take good care of them.



In 2015, a bomb went off near Erawan Shrine, a popular tourist spot in the capital. The attack killed 20 people and injured more than 120 others, including a Japanese national. A month before, Thailand had sent over 100 Uyghurs back to China.