Tests were widely conducted in the provinces of Songkhla, Satun, Trang, Phatthalung, Pattani, Yala and Narathiwat after a student returning from South Africa tested positive in Malaysia.
However, the person has been quarantined and all close contacts are being monitored and tested, Malaysian authorities say.
As for calls to reopen the Thai-Malaysia border, Ratchada said the Centre for Covid-19 Situation Administration (CCSA) is considering the proposal and will come up with a solution after its meeting on December 13.