The strike is the first known US military operation in the Pacific since US President Donald Trump's administration started a new offensive against the drug trade that has led to at least seven strikes in the Caribbean and dramatically raised US tensions with Venezuela and Colombia.
The official, speaking on condition of anonymity, did not provide further details but said there were several people - suspected to be smugglers - on the vessel when it was struck.
The Pentagon did not immediately respond to a request for comment.
The latest strike, which was first reported by CBS News, comes against the backdrop of a US military build-up in the Caribbean that includes guided missile destroyers, F-35 fighter jets, a nuclear submarine and about 6500 troops.
Legal experts have questioned why the US military is carrying out the strikes, instead of the Coast Guard which is the main US maritime law enforcement agency, and why other efforts to halt the shipments are not made before resorting to deadly strikes.
In August, the Coast Guard launched an operation known as Operation Viper to interdict drugs in the Pacific Ocean.
As of October 15, the Coast Guard said it had seized more than 100,000 pounds of cocaine.
It was unclear why the administration carried out a strike in this instance instead of interdicting the vessel.
The strikes in the Caribbean have killed at least 32 people but the US administration has provided few details, such as how many alleged drugs the vessels were carrying or what specific evidence it had to suggest they were carrying drugs.
9°C