Federal authorities seized 16.5 tons of cocaine worth more than $1 billion from a ship in Philadelphia in one of the largest drug seizures in U.S. history, the U.S. Justice Department said on Tuesday.

Federal, state and local law enforcement agents on Monday boarded the MSC Gayane, a cargo ship docked in Philadelphia's Packer Marine Terminal, and found cocaine in seven shipping containers, according to a criminal complaint filed in Philadelphia federal court.

Federal authorities arrested and charged two of the ship's crewmembers Ivan Durasevic and Fonofaavae Tiasaga. Both men told investigators how they helped load the ship with cocaine during its voyage, the criminal complaint showed.

"This amount of cocaine could kill millions - MILLIONS - of people," Philadelphia-based U.S. Attorney William McSwain said on Twitter, announcing the seizure on Tuesday. His office estimated the value of the cocaine seized at more than $1 billion.

The ship was in Chile, Peru and Colombia and Panama over the last month, according to Reuters vessel tracking data.

The cargo ship owner Mediterranean Shipping Company said in a statement that it was aware of the incident and that it has a history of working with U.S. law enforcement agencies to help disrupt illegal narcotics trafficking.

The seizure ranks among some of the largest in U.S. history including a bust of 21 tons of cocaine in California in 1989 and 14 tons of cocaine confiscated in Texas during the same year.

Cocaine remains one of the most widely used illegal drugs in the United States, where most of the world's cocaine is consumed, according to federal officials.

"There are troubling early signs that cocaine use and availability is on the rise in the United States for the first time in nearly a decade," the U.S. State Department said in a global narcotics trade report in 2017.