A combined force of the Burapha Task Force, military rangers and police yesterday set up checkpoints near the border to monitor those who entered at the Aranyaprathet crossing.
Pol Lt Col Benjapol Rodsawat, deputy chief of Sa Kaeo immigration police, said more than 450 Cambodian Muslims passed through the border on Friday.
They told authorities they were travelling to Pathum Thani's Khlong Luang district for a religious rite, he said.
Up to 149 Cambodian Muslims had also crossed the border from Saturday to yesterday, Pol Lt Col Benjapol said, adding they all held legitimate passports.
Authorities are concerned the border crossers will join the demonstrations in Bangkok.