Acting on a tip-off, department officials conducted a raid near Folkland Park in the Falkland neighbourhood on Wednesday, department spokesperson Peter Zohmingthanga said.
During the operation, officials recovered 10.021 kg of methamphetamine, totalling around 1 lakh tablets, he said.
Two residents of Assam's Karimganj, identified as Jakaria Hussain (28) and Taj Uddin (25), were arrested at the scene, he said.
Follow-up investigations also led to the arrest of two more individuals later in the day.
Lalnunziri (38), a Myanmar national from Khawmawi village believed to be the supplier, was arrested in the Khatla neighbourhood around 4:30 pm, while Vanlalrintluanga (27), a resident of Armed Veng South in Aizawl, was taken into custody around 7 pm for allegedly facilitating the local transport of the consignment, he said.
He added that officials also confiscated a Maruti WagonR car used to transport the consignment.
Zohmingthanga further said that five mobile phones, reportedly used to coordinate the deal, were seized from the suspects.
He said the consignment was intended for distribution in Assam.
The four accused have been booked under Section 21(c) of the Narcotic Drugs and Psychotropic Substances (NDPS) Act, 1985, and were produced before the Special NDPS Court in Aizawl on Thursday, he said.
According to Zohmingthanga, the operation is part of an intensified "Special Drive" launched ahead of the Aizawl Municipal Corporation (AMC) elections scheduled for April 21.
The Excise department has so far seized 7.238 kg of heroin, 49.392 kg of methamphetamine, and 90.836 kg of ganja, along with other narcotic substances, since January, he added.