Chiang Mai deputy governor Chana Paengpiboon said security will be tightened along the border, because drug trafficking rings could benefit from the festival period for their operations.
Last night, Region 5 police killed two men as they were trying to smuggle 400,000 methamphetamine pills from the border in Chiang Rai to Chiang Mai.
Police are conducting an investigation for further arrests.
Mr Chana said Bt500 million in assets believed to be linked to drug syndicates were seized during the first quarter of this year.
Meanwhile, Region 8 Police commander Pol Maj Gen Veerasak Meenavanich said three suspects were arrested in Nakhon Si Thammarat's Thungyai district with 50,000 methamphetamine pills hidden in their pick-up truck.
The two Thai men and one Myanmar woman confessed to bringing the pills from Myanmar via Three Pagodas Pass in Kanchanaburi province.
They said this was their first time to smuggle drugs.