Tehran said Saturday that the crew of two Greek oil tankers seized by Iran in the Gulf a day earlier have not been detained, contradicting comments from Greece's Foreign Ministry.

"The crew of the two Greek tankers have not been arrested, and all crew members ... are in good health and are being protected, and provided with necessary services while on board [their ships]," the country's Ports and Maritime Organization said in a statement carried by state media.

The two vessels, Delta Poseidon and Prudent Warrior, both sailing under the Greek flag, were stopped by Iran's Revolutionary Guards over unspecified "maritime violations," the body said.

The ships are both Suezmaxes, a term for the largest ships that can traverse the Suez Canal, and had just come from Iraq's Basra oil terminal, loaded with crude, according to tracking data from MarineTraffic.com.

Athens said crews were 'held captive'

Hours after Friday's incident, Greece said the crew of both ships — 44 people between them — were being "held captive" after Iranian navy helicopters landed gunmen on the two tankers.

Athens said the seizure was "tantamount to acts of piracy," demanded the immediate release of the crews and called for the ships to be allowed to continue their journey.

Athens also notified all Greek ships in the Gulf and called on Greek citizens to avoid traveling to Iran.

The seizure of the two tankers was in apparent retaliation for the confiscation last month by Greece of an Iranian oil tanker — Lana — held off the Greek coast on behalf of the United States.

Russia-linked ship carried Iranian oil

The Lana and its Russian crew were later released after the oil cargo was removed, Reuters news agency reported on Thursday.

Greek media said the Lana had only been stopped because the ship sought refuge in April from a powerful storm in a bay on the Greek island of Euboea.

Authorities found that the tanker belonged to Russia's Promsvyazbank, a state-backed, formerly private Russian bank from Moscow, which is subject to EU sanctions.

According to the reports, it later transpired that the tanker had been sold to a non-sanctioned Russian bank in March and was due to be released.

Authorities then found that the tanker was carrying Iranian oil and the US authorities demanded that it remain confiscated, Greek media said.

String of similar incidents

The latest incidents bear similarities to the seizure by Iran of a British tanker near the Strait of Hormuz in 2019, two weeks after British forces detained an Iranian oil ship near Gibraltar, accusing it of shipping fuel to Syria in violation of European Union sanctions.

Iranian hijackers also stormed and briefly captured a Panama-flagged asphalt tanker off the United Arab Emirates last year, and briefly seized and held a Vietnamese tanker in November.

In addition, Iran last year seized and held a South Korean-flagged tanker for months amid a dispute over billions of dollars of frozen assets Seoul holds.

Tensions between Iran and the West remain high over Tehran's 2015 nuclear deal, which is now in jeopardy after the US pulled out of the agreement in 2018.

Tehran is enriching more uranium, closer to weapons-grade levels than ever before, which has raised concerns that there could be no way of reviving the deal.

mm/wd (AFP, AP, dpa, Reuters)