According to US Homeland Security Secretary Kristi Noem, the tanker had passed through Venezuelan waters and "acted in defiance of President (Donald) Trump's established quarantine for sanctioned ships in the Caribbean."
It is the sixth tanker the US has seized in recent months.
The boarding, which took place just before dawn on Thursday, local time, occurred just hours before Venezuelan Nobel laureate María Corina Machado's visit with Trump at the White House.
