China has seized more than 2,700 ivory tusks in what customs authorities are calling the country's biggest smuggling case in years.

China's Customs Administration announced Monday that it confiscated nearly 7.5 tons (6,803 kilograms) of ivory on March 30.

Authorities said the illicit goods came from an international criminal group that has been smuggling ivory for some time. Twenty suspects are now in custody.

Since the start of the year, customs officers have seized a total of 8.5 tons (7,711 kilograms) of ivory products through 53 investigations. An additional 129 cases involved the smuggling of other endangered animal products, such as shark fin and turtle shells.

China has cracked down on smuggling in recent years and implemented in 2018 a total ban on all trade in ivory products.