The New York authorities seized $4.5 million worth of illegal elephant ivory items in what they described as the biggest bust in the state's history, officials said Thursday.

Ivory items put on display for reporters included scores of statuettes, a carved column, two pairs of tusks and a chess set.

Two pairs of tusks -- an adult elephant's and another from a young adult -- were valued at $200,000 and $150,000, respectively.

The ivory came from at least 12 slain animals, officials said.

"We are going to dry up... a market that only fuels the slaughter of elephants," Manhattan District Attorney Cy Vance said. "It is inexcusable, it is immoral."

New York City is a hub of illegal elephant ivory trade, ahead of California and Hawaii, said Basil Seggos, head of the state's Department of Environmental Conservation. His office participated in the probe.

"This type of behavior will no longer be tolerated," he said.

New York was one of the first states in 2014 to adopt strict laws banning ivory sales to protect elephants, Vance said.

Undercover police posing as buyers seized the latest items at a midtown Manhattan art and antiquities store.

Although officials said they were not certain where the items came from, they did say most ivory craftsmen are found in China.

It is illegal to sell elephant ivory without a special license. But New York's rules were tightened so much in 2014 that they effectively banned ivory sales except under limited circumstances.

Although the store had a license, it expired two years ago and could not be renewed because of the new restrictions.

The store owners were indicted on charges of illegal commercialization of wildlife. They face hefty fines and up to three years in prison.

The United States and China, among the world's biggest ivory consumers, have agreed to enact near-total bans on their domestic markets.

The Convention on International Trade in Endangered Species (CITES) banned the international commercial trade in African elephant ivory in 1989.

But illegal poaching of endangered elephants for their tusks persists at dangerous levels.

Savanna elephants have declined at a rate of 27,000 -- or eight percent -- per year, with a total of 144,000 lost in less than a decade.