Iranian coast guards seized control of a foreign ship for allegedly smuggling Iranian oil, its media reported on Saturday.
According to the Iranian Fars news agency, the coast guards stopped the ship carrying about 284 thousand liters of smuggled Iranian oil near the Strait of Hormuz.
The Iranian news agency also reported that the coast guards arrested the 12 Philippine nationals on the ship and referred them to the country's judicial authorities.
No comment was made by the US Navy command based in Bahrain which usually follows such incidents.
In July, Iran seized a British-flagged oil tanker and arrested its seven crew members. The incident came as a response to the British seizure of an Iranian tanker in Gibraltar. Arrested crew members were later released.
Iran, which has some of the world's cheapest fuel due to heavy state subsidies, has been fighting rampant fuel smuggling overland to neighbouring countries and by sea to Gulf Arab states. It has frequently seized boats it says are being used for smuggling fuel in the Gulf.
The incidents come at a time of tensions between Iran and the West in the Gulf that have been rising since the United States exited world powers' 2015 nuclear deal with Tehran last year and reimposed sanctions.
While Iranian media reports say an estimated 10 million litres of fuel are smuggled per day, Tehran has been promoting legal gasoline exports through its energy bourse.
Gasoline sales hit a record high of $72 million last week on the Iran Energy Exchange (IRENEX) for exports to neighbouring countries, according to state TV.