"Overnight, US military forces conducted a right-of-visit, maritime interdiction and boarding on the Aquila II without incident," Hegseth wrote in a post on X.
"It ran, and we followed."
After capturing Venezuelan president Nicolas Maduro in a military raid last month in Caracas, the US has escalated its blockade on vessels that are under sanctions and going to and from the South American country, a member of the OPEC oil producers group.
Suezmax tanker Aquila II departed from Venezuelan waters in early January as part of a flotilla of vessels.
It was carrying about 700,000 barrels of Venezuelan heavy crude bound for China, according to schedules from state company PDVSA.
Most tankers in the flotilla have returned to Venezuela or have been seized by the US.
Hegseth said the Aquila II was operating in defiance of the US "quarantine of sanctioned vessels in the Caribbean".
"The Department of War tracked and hunted this vessel from the Caribbean to the Indian Ocean ...You will run out of fuel long before you will outrun us," he wrote.
It was unclear where the Aquila II was registered, according to shipping databases.
