Two persons have been arrested and booked under the Arms Act. The accused have been identified as Thangdeihtung and Liankhanmanga, both 30 years of age and residents of Champhai town, near the Indo-Myanmar border.
Top police sources said law enforcement agencies acted on a tip-off received by the North Vanlaiphai Police station on Monday afternoon, which indicated the arms cache was moving from Champhai towards Lunglei town in south-central Mizoram through Serchhip.
The accused were stopped just outside Khawlailung village later in the evening. They were riding a pick-up truck, and the rifles were stashed in a compartment behind the front seats while the rest were wrapped in a silpaulin sheet and placed in the rear.
Interrogations have revealed the duo were given the consignment by one Thanglianpaua in Champhai, who told them a man he did not name would get in touch with them through one of the mobile handsets he gave them and receive the consignment near Lunglei.
Investigators have ruled out the consignment's connection with any election-related use by militants or other groups, but have also not yet been able to gauge which group or groups are likely behind it.
Mizoram, one of North-East India's most peaceful states, has in the past few years become a major route for arms and narcotics traffickers.
In March this year, police and Assam Rifles had seized 31 AK-47 assault rifles, an LMG, a US-made Browning automatic rifle, more than 800 rounds of ammunition and 32 magazines from a hut near the state's lone domestic airport at Lengpui, just 30-km from capital Aizawl. Three Chakma tribesmen believed to be from Bangladesh were arrested in connection with the seizure.
Law enforcement agencies said later the consignment was meant for the Parbotia Chatagram Jana Sangata Samiti (PCJSS), based in Bangladesh's Chittagong Hill Tracts, and that the arms and ammunition came from Myanmar. The National Investigation Agency (NIA) has since taken over the case.
In 2009, Mizoram Police had also seized a consignment of eight M-16 assault rifles, considered one of the largest seizures in the state's history when the quality of arms is taken into account.