Three suspects were arrested in the northern province of Phayao late Sunday night with 400 kilogrammes of 'ice' and ketamine in two ambulances normally hired for emergency services in Pathum Thani province.
Police followed the two ambulances from the northernmost province of Chiang Rai and made arrest attempts in Phayao.
Suspects fired at policemen trying to stop the ambulances on Soi Sri Samran, tambon Dok Kham Tai, Phayao's Dok Kham Tai district, at about 8.30pm. Police then shot a front tyre of one of the ambulances. It lost control and all the other tyres burst.
The other ambulance was finally stopped at a checkpoint in Muang Phayao district. Police found a total of 300kg of crystal meth or "ice" and 100kg of ketamine in plastic packs in the vehicles.
The suspects, who were not identified, were brought together with the ambulances to the Provincial Police Region 5 in Chiang Mai province.
Rangsan Nantakawong, mayor of Bueng Yitho municipality in Thanyaburi district of Pathum Thani, said on Monday that the two ambulances and their staff were of a private company that the Pathum Thani health office hired for emergency services in the municipality. His municipal office supervised the payment of money from the health office to the contractor.
He said the municipal office dismissed the company from the services in Bueng Yitho and would ask rescue foundations to fill in until the provincial health office could find a new contractor.