Brigadier General Ali Ozmaei, an IRGC commander, said on Monday that the vessel, manned by 11 crew members, was detained near the Strait of Hormuz when it was smuggling the fuel to the United Arab Emirates (UAE).
"This boat was sailing from [Iran's] Bandar Lengeh towards the United Arab Emirates before it was seized 32 kilometers east of the Greater Tunb island in the Persian Gulf," Ozmaei said.
"The boat's 11 crew members have been handed over to legal authorities," he added, without elaborating on the nationalities of the crewmen.
State television also broadcast footage from the deck of the vessel with open hatches that showed tanks full of fuel.
It is the second such seizure of fuel-smuggling ships by Iranian forces this month.
On September 7, Iranian coast guards seized a vessel smuggling nearly 284,000 liters of fuel and detained its 12 Filipino crew members in the Strait of Hormuz.
In another incident on July 19, the IRGC impounded the 30,000-tonne UK-flagged Stena Impero tanker as it was passing through the Strait of Hormuz en route to Saudi Arabia “for failing to respect international maritime rules.”
The vessel had been involved in an accident with an Iranian fishing boat and had ignored its distress call, changing its route.
The reports come amid tough situation in the Persian Gulf, where the United States has been trying to persuade its allies into an international coalition with the declared aim of providing “security” for merchant shipping in the Strait of Hormuz — through which about a fifth of all oil consumed globally passes — and other strategic Middle Eastern shipping lanes.
Washington claims Tehran has played a role in two separate attacks on oil tankers in the Gulf of Oman in May and June, without providing any credible evidence to support the accusations, which Iran has categorically rejected.