The vessel was towed on Sunday after a distress call and it was later seized for fuel smuggling, it added.
An oil tanker based in the United Arab Emirates disappeared off trackers as it sailed in the Gulf on Sunday.
A Panamanian-flagged oil tanker, the MT Riah stopped transmitting its location overnight on Sunday near Qeshm Island, which has a Revolutionary Guard base stationed on it.
Iran’s state television station did not identify the vessel.
It quoted the Revolutionary Guards as saying the ship had been smuggling one million litres of fuel.
The move came at a time of mounting tensions between the US and Iran over the unravelling nuclear deal between Tehran and other world powers.
The UK foreign office said it was seeking further information following reports of the seized tanker, adding it continued to urge the Iranian authorities to de-escalate the situation in the region.