Tanzanian authorities seized tusks from about 45 elephants and arrested two suspects at their home in the commercial capital Dar es Salaam, police
The 156 pieces of ivory weighed more than 200 kg (440 pounds) and were worth 1.43 billion Tanzanian shillings ($670,000), according to a police statement issued late on Tuesday.
Elephant poaching has been widespread in the East African country, which relies heavily on revenue from safari tourism, just when neighboring Kenya has noted a steep drop.
Tanzania's new president, John Magufuli, has pledged to root out poaching as part of a wider war on corruption, and to crack down on gangs that kill elephants and rhinos to feed Asian demand for ivory and horns for use in traditional medicines.
Dar es Salaam police chief Suleiman Kova said that two rifles had been taken from the two Tanzanian suspects and that law enforcement officials were "working closely with wildlife officials to speed up our investigation."
Tanzanian authorities have made progress in their crackdown on the illegal trade in recent months. In October, Tanzania charged prominent Chinese businesswoman Yang Feng Glan, 66, dubbed the "Ivory Queen," with running a network that smuggled tusks from 350 elephants.
Tanzania's elephant population shrank to about 43,000 in 2014 from 110,000 in 2009, according to a census released in June, with conservationists blaming "industrial-scale" poaching.