The Iranian navy escorted Advantage Sweet to a port based on an "international dispute," announced Advantage Tankers.
On Thursday, Iran's navy seized a Marshall Islands-flagged oil tanker heading to the US in the Gulf of Oman.
Advantage Tankers, which owns Advantage Sweet, said the Iranian navy had transferred it to an unnamed port, according to the Agence France-Presse (AFP).
"TankerTrackers" website, which specializes in tracking ship movements, said on Twitter that the vessel was located in the anchorage of Bandar Abbas in Iran "as expected."
The US Navy said that forces from Iran's Revolutionary Guards Corps (IRGC) seized the tanker, which was flying the Marshall Islands flag while it was sailing in international waters.
The commander of the US CENTCOM, General Michael Kurilla, said in a statement that the "illegal seizure" of the tanker was "another in a continuing series of violations by Iran of the international rules-based order."
"This kind of harassing activity is commensurate with an established pattern of Iranian behavior that places the security and stability of the Middle East at risk," warned Kurilla.
The Iranian army said a Marshall Islands-flagged oil tanker was seized by the naval force in the Arabian Gulf after "it collided with an Iranian boat in the Gulf of Oman and tried to flee."
It indicated that two members of the boat's crew were missing, and several were injured due to the ship's collision with the boat.
Later, Maritime security company Ambrey said the vessel had been boarded via helicopter. "The vessel did not show any signs of conducting evasive maneuvers before the incident," it said.
Munro Anderson, who works with Maritime security company Dryad, said separately that Iran usually detained vessels for "leverage or signaling."
"The working hypothesis at the moment is that it could either be an arbitrary detention of a vessel by Iran in response to the US sailing its first unmanned vessel through the region last week - as a show of force," he said.
Anderson noted that it could be in response to the US sanctions announced on Apr. 24 against personnel in Iran connected to the IRGC.
According to Refinitiv ship tracking data, it is a Suezmax crude tanker chartered by oil major Chevron and last docked in Kuwait.
The vessel's destination was the US Gulf of Mexico port in Houston.
Advantage Tankers stated that the tanker was carrying 24 Indian crew members, stressing that the company" was "in close touch with all the appropriate authorities to obtain the release of the crew and vessel."
Past experience shows that crew caught up in similar incidents are in "no danger," the ship's operator, Advantage Tankers, told AFP.
Since 2019, there have been a series of attacks on ships in strategic Gulf waters at times of tension between the US and Iran.
The development came when Iran's oil exports increased despite US sanctions over its nuclear program.
Last year, the US tried to seize an Iranian oil shipment off the coast of Greece, prompting Tehran to hold two Greek-flagged tankers in the Gulf.
Greece's Supreme Court ruled that the shipment should be returned to Iran. The two Greek tankers were later released.
Senators from the Democratic and Republican parties urged US President Joe Biden to enable a federal government agency to seize Iranian oil and gas shipments.
Senators Joni Ernst, a Republican, and Richard Blumenthal, a Democrat, said in a letter to Biden that the Department of Homeland Security's Investigations (HSI) office has been unable to seize an Iranian oil shipment for more than a year.
HSI's enforcement has been curtailed by policy limitations within the Department of Treasury's Executive Office for Asset Forfeiture, the senators said in the letter, a copy of which was reviewed by Reuters.
The senators said that since the activation of HSI's enforcement program in 2019, it had seized nearly $228 million in Iranian crude and fuel oil linked to Iran's Quds Force.
Iranian Oil Minister Javad Owji said last month that Iranian oil exports had reached their highest levels since re-imposing US sanctions in 2018.
He added that 83 million barrels more oil was exported last year.
The letter, signed by 12 senators, was sent on the same day the seizure was announced.
"While Iran is seizing ships, our own program is completely languishing," an aide to Ernst told Reuters.
Indirect negotiations between Iran and the United States on reviving the 2015 nuclear deal have reached a dead end.
Iran says its nuclear program is for civilian purposes, while the US suspects Iran wants to develop a nuclear bomb by accumulating highly enriched uranium.
