Police seized the drugs from a vehicle, on its way from Uttar Pradesh to Manipur from where it would have been moved to Myanmar, at Manja about 16 km from here late last night.
More than two lakh tablets of IT-1 PR tablets worth over 13 lakh were seized and the three persons in the vehicle were arrested, police said.
The arrested have been identified as Aftabuddin, Dilip Khan and Imzad Khan.