Federal authorities seized 15,000 kilos of cocaine, worth as much as $1 billion, at a Philadelphia shipping port, officials said Tuesday. A second mate and a crew member have been arrested in the massive bust.

There were 16.5 tons of the drug found in seven shipping containers late Monday night, officials said.

“This is one of the largest drug seizures in United States history," U.S. Attorney for the Eastern District of Pennsylvania William McSwain tweeted. "This amount of cocaine could kill millions — MILLIONS — of people. My Office is committed to keeping our borders secure and streets safe from deadly narcotics."

The street value of all the seized cocaine could be as high as $1 billion, according to federal prosecutors in Philadelphia.

The illicit haul was found aboard a cargo ship, the MSC Gayane, which had traveled from Chile, Panama and the Bahamas, according to NBC Philadelphia.

Federal authorities in Pennsylvania arrested and charged two of the MSC Gayane's crew members with intentionally conspiring to possess with the intent to distribute.

Homeland Security Investigations has filed an arrest warrant affidavit which details how Ivan Durasevic and Fonofaavae Tiasaga allegedly coordinated the loading of cocaine onto the vessel.

The court document says that Durasevic, the crew's second mate, admitted his role in bringing the cocaine on the vessel. It says that he got a call from the chief officer to go to the deck after the vessel left Peru, at which time he saw nets on the port side (left side facing the bow) by the ship's crane. The document says Durasevic and approximately four other individuals, some wearing ski masks, assisted in pushing the nets containing blue and black bags of cocaine into the hold and loaded them into containers.

Durasevic later allegedly told agents that he was paid $50,000 for his role in the scheme. He allegedly told the feds that Tiasaga was one of the crew members who helped him load the cocaine.

Tiasaga allegedly told agents that it was Durasevic who operated the crane that brought on the bales of the cocaine after the MSC Gayane was approached by six separate boats during the night while the ship was sailing between Panama and Coronel. He says an additional eight boats brought more cocaine as the vessel moved north between Coronel, Peru and Panama.

Agents write that additional container seals were brought aboard to re-seal the containers loaded with cocaine.

The court documents say that Durasevic's arms and hands tested positive for the presence of cocaine.

The arrest affidavit says that the drugs were found upon search of the vessel in seven separate shipping containers, as we have reported.

The shipping company MSC thanked federal authorities for making the bust.

"MSC takes this matter very seriously and is grateful to the authorities for identifying any suspected abuse of its services," according to a company statement.

"Unfortunately, shipping and logistics companies are from time to time affected by trafficking problems. MSC has a longstanding history of cooperating with U.S. federal law enforcement agencies to help disrupt illegal narcotics trafficking and works closely with U.S. Customs and Border Protection (CBP)," the statement said.

Deaths linked to cocaine abuse have been on the rise, according to the Centers for Disease Control and Prevention.

The troubling trend began around 2012, before cocaine-related deaths jumped 34 percent from 2016 to 2017, the CDC said.