April 27, 2023 | Flash Brief

Iran Seizes U.S.-Bound Oil Tanker

April 27, 2023 | Flash Brief

Iran Seizes U.S.-Bound Oil Tanker

Latest Developments

Iranian naval forces seized a Marshall Island-flagged oil tanker traveling through international waters in the Gulf of Oman on April 27. The tanker, Advantage Sweet, was transporting oil from Kuwait bound for Houston, Texas, when Iran captured it around 1:15 p.m. local time just north of Oman’s capital, Muscat.

The U.S. Navy’s Fifth Fleet, which patrols the Red Sea, Persian Gulf, and Arabian Sea, called the seizure a violation of international law and demanded the tanker’s immediate release. Earlier in April, the Fifth Fleet issued a warning advising all ships — especially Israeli ones — to proceed cautiously through the area due to an increased threat of Iranian harassment. According to the U.S. Navy, Iran has unlawfully seized at least five commercial vessels sailing through the region over the past two years.

Expert Analysis

“Threats to international maritime commercial traffic cannot be tolerated. The response from Washington and its allies should be resolute in demanding the ship’s immediate release while quickly ratcheting up pressure on the regime in meaningful and creative ways.” Richard Goldberg, FDD Senior Advisor

“The regime in Tehran has learned that it very rarely pays a price for taking hostages, regardless of whether they are ships or people. Instead of treating hostage-taking as a standard part of the Western give-and-take with Iran, the United States and its allies need to exact a price from Tehran for subverting basic rules that help avoid war in a volatile region.” David Adesnik, FDD Senior Fellow and Director of Research

Iran’s Record of Attacks and Seizures

Iran has been threatening commercial shipping in the region for years. In May 2019, Iran used mines to damage Saudi Arabian, Norwegian, and United Arab Emirates (UAE) tankers near the UAE’s Fujairah port. In June 2019, mines likely planted by Tehran damaged Japanese and Norwegian tankers near the Strait of Hormuz. Iran seized the British-flagged tanker Stena Impero that same year, detaining the ship and crew members for over two months. 

In January 2021, Iranian forces seized the South Korean tanker MT Hankuk Chemi near the UAE coast after it had passed through the Strait of Hormuz. Iran released the ship and its captain four months later. In July 2021, an Iranian drone off the coast of Oman attacked the MT Mercer Street, a Japanese-owned, Israeli-managed cargo ship, killing two crew members.

In May 2022, Iran seized two Greek oil tankers — the Delta Poseidon and the Prudent Warrior — in the Persian Gulf in response to the U.S. seizure, with Greek assistance, of the Iranian vessel Lana near the Greek island of Evia. The Lana had been violating U.S. sanctions by transporting crude oil. Iran released the ships in November after lengthy negotiations between Athens and Tehran.

Further Analysis

U.S. Sends Submarine to Middle East to Counter Iranian Threats to Maritime Trade,” FDD Flash Brief

U.S. Carrier Strike Group Transits Strait of Hormuz,” by Bradley Bowman and Andrew Gabel

To Stop Iran’s Proxy Terrorists, Stop Iran,” by Bradley Bowman, Joe Truzman, and Ryan Brobst


Iran Iran Global Threat Network Israel