MILWAUKEE (REUTERS) - US authorities seized about 18.5 tonnes of cocaine with a street value of US$500 million (S$686.15 million) in the eastern Pacific Ocean, the US Coast Guard said on Friday (Nov 16).

The cocaine was taken off the Coast Guard cutter James in the Port Everglades in Fort Lauderdale on Thursday after it was confiscated from 15 drug smuggling vessels in the international waters, the Coast Guard said.

Multiple US Coast Guard cutters helped seize the drugs from Mexico, Central and South America, it said.

A total of 49 suspects were also arrested and will be prosecuted in southern Florida, the Miami Herald reported.

Cocaine remains one of the most popular 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 US State Department said in a global narcotics trade report in 2017.

Potential global cocaine output reached 1,410 tonnes in 2016, the highest level ever estimated, the United Nations said in a report on drugs and crime in 2018.