Eighteen Indians are reportedly among 23 crew members in a British-flagged tanker seized by Iran’s Revolutionary Guards Corps (IRGC) in the Strait of Hormuz on Friday for breaking “international maritime rules” as tensions mount in the highly sensitive waterway.

“The British vessel was captured for failing to respect the international maritime rules while passing through the Strait of Hormuz,” said the statement released by Public Relations of the IRGC.

The oil tanker was delivered to Iran’s Hormozgan Ports and Maritime Organization at the Iranian coast for further legal procedures, the statement added.

The British oil tanker, Stena Impero, confiscated by the Iran guards, had 23 seafarers onboard of Indian, Russian, Latvian and Filipino nationality, according to Erik Hanell, president and chief executive of Stena Bulk, the tanker’s operator.

According to an AFP report, 18 crew were Indian, including the captain, and the rest were from the Philippines, Latvia and Russia.

However, there has been no official announcement from the Indian government.

According to a report in Reuters, Stena Bulk in a statement said that the ship was no longer under the crew’s control and could not be contacted.

Britain meanwhile, has claimed that Iran had seized two ships in the Gulf, with Foreign Secretary Jeremy Hunt warning of “serious consequences” if the issue was not resolved quickly.

However, the other ship, the Liberian-flagged Mesdar was set free after it was temporarily boarded by armed personnel, the owner of the tanker said.

The latest incident came as President Donald Trump insisted Friday that the US military had downed an Iranian drone that was threatening an American naval vessel in the Strait of Hormuz, despite denials from Tehran.

The incident came as IRGC announced that it had seized a foreign ship “smuggling fuel” in the Gulf on Thursday, days after reports of a British tanker being harassed in the region.

Iran categorically denied the allegation and deputy foreign minister Abbas Araghchi tweeted that American forces may have shot down a US drone by mistake.

Tanker tracking service Marine Traffic showed that the Swedish-owned Stena Impero last signalled its location near the Island of Larak in the highly sensitive waterway, according to a report in AFP.

The ship was transiting the Strait of Hormuz and in “international waters” when it was “attacked by unidentified small crafts and a helicopter,” the owner said.

Tensions in the Gulf have soared in recent weeks, with Trump calling off airstrikes against Iran at the last minute in June after Tehran downed an American drone, and blaming Iran for a series of tanker attacks — charges the Islamic Republic denies.

The latest escalation comes more than a year after Washington unliterally withdrew from the 2015 Iran nuclear agreement and began ratcheting up sanctions against Tehran.