Thai airports have been ordered to strictly screen all Cambodians entering Thailand under the visa-free scheme and to also tighten checks against foreign mercenaries entering the country, amid the conflict at the border.
The Immigration Bureau on Monday asked foreign tourists to understand the situation, which could result in congestion at passport control.
Enhanced security measures apply mainly at Suvarnabhumi, Don Mueang, Chiang Mai, Phuket and Hat Yai airports.
There was a possibility that foreigners might exploit the visa-free entry scheme to carry out operations that threaten Thai security, immigration police said. It was most unlikely that Cambodians would come here for tourism at this time, they said.
Cambodian nationals entering for business are required to obtain proper visas from the Thai embassy.
Another focus group is passengers from eastern Europe and northern Asia, who might be hired as a mercenaries, or even as spies, police said.
The waiting time at immigration control queues could be extended from the usual 20 minutes to around 45 minutes. This would not affect Thai travellers. Commercial flights between Thailand and Cambodia were still operating as usual.
