Dramatic footage has been released of a US coast guard member pouncing onto a homemade
as it threatens to descend below the ocean's surface.
The 12m-long submarine was carrying nearly eight tonnes of cocaine and being smuggled via the Pacific Ocean into the US.
The video shows a Coast Guard member in military fatigues jumping onto the roof of the submarine and banging on the hatch, demanding it be opened.
'Stop your boat now,' the guardsman shouts in Spanish.
The hatch soon opens and the man inside emerges with his hands in the air.
The video was filmed on June 18 but was only released today.
The so-called 'narcosub' is one of 14 drug-smuggling boats intercepted by the US Coast Guard in the last three months, resulting in the seizure of 18 tonnes of cocaine.
'Make no mistake about it, Coasties, your courageous service is saving American lives,' Vice President Mike Pence said at an event in San Diego overnight.
About 90 percent of Colombian cocaine enters the United States via the Pacific corridor.
© Nine Digital Pty Ltd 2019