It gave no details of the date of the incident or the country where the vessel is registered.
The report comes amid faltering efforts to revive Iran’s nuclear deal with world powers that would see a lifting of US sanctions on its oil exports.
The sequence of events reported by the television station left key questions unanswered.
“The United States stopped a tanker exporting Iranian oil and transferred its cargo to another tanker which it directed towards an unknown destination,” it said.
“The naval arm of Iran’s Revolutionary Guards then captured the tanker with air support,” it said, without specifying which vessel it was referring to.
“US forces again tried to block the passage of the tanker using a warship and several helicopters but again failed.
“The tanker is now in Iranian territorial waters,” it said.
The Islamic Revolutionary Guard Corps has video of the incident that it plans to release, Iran’s Mehr news agency reported.
Under the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action and signed between Iran and world powers, Washington had lifted its sanctions on Iran’s oil exports in return for strict limits on Iran’s nuclear activities to prevent weapons development.
But in 2018, then US president Donald Trump abandoned the agreement and reimposed the sweeping sanctions, saying the JCPOA did not go far enough in preventing Iran from obtaining nuclear weapons. Iran responded by dropping some of its commitments to the pact and increasing its uranium enrichment, which has raised concerns it is nearing the threshold for nuclear weapons production.
US President Joe Biden has expressed willingness to rejoin the deal in exchange for Iran returning to the limits on its nuclear activities, but talks in Vienna on the practicalities have been suspended since June.
Iran said last month that it will return to the Vienna talks, which are sponsored by the European Union, but the US remains skeptical of its true intentions and no date has yet been set for a meeting.
The US has in the past seized crude oil from an Iranian tanker and then sold off the cargo.
On Tuesday, Iran’s ISNA news agency said the country’s navy had prevented pirates from seizing another tanker in the Gulf of Aden in the second such incident in a fortnight.
Pirates also attacked a convoy of two vessels on October 16.
Like other countries dependent on the shipping route through the Red Sea and Suez Canal, Iran stepped up its naval presence in the Gulf of Aden after a wave of attacks by Somalia-based pirates between 2000 and 2011.
But the number of attacks has fallen sharply in recent years.
