Iran has seized a second oil tanker in a week on Wednesday in Persian Gulf waters, the US Navy said, the latest escalation in a series of attacks on commercial vessels since 2019.

The Bahrain-based US Fifth Fleet said the Panama-flagged oil tanker Niovi was seized by Iran's Islamic Revolutionary Guard Corps Navy (IRGCN) at 6:20 a.m. (0220 GMT) while passing through the narrow Strait of Hormuz.

The incident comes after Iran on Thursday seized a Marshall Islands-flagged oil tanker in the Gulf of Oman called the Advantage Sweet. That tanker is being held by Iranian authorities in Bandar Abbas, the Marshall Islands flag registry said on Tuesday.

Maritime security firm Ambrey has said it believed the Advantage Sweet's seizure by Iran was in response to a recent seizure via a court order by the United States of an oil cargo aboard the Marshall Islands tanker Suez Rajan.

The Niovi oil tanker had been travelling from Dubai toward the UAE's Fujairah port when it was forced by IRGC boats to change course towards Iranian territorial waters, the Navy said.

The Niovi last reported its position at 0231 GMT on Wednesday off the coast of Oman in the Strait of Hormuz with Fujairah as its destination, Refinitiv ship tracking data showed.

According to the International Maritime Organization shipping database, the Niovi's owner is Grand Financing Co, and the ship is managed by Greece-based Smart Tankers.

"Heightened military activity and geopolitical tensions in these regions continue to pose serious threats to commercial vessels," the Marshall Islands flag registry said in an advisory on Tuesday.

"Associated with these threats is the potential for miscalculation or misidentification, which could lead to aggressive actions."

Since 2019, there have been a series of attacks on shipping in the strategic Persian Gulf waters at times of tension between the United States and Iran.

Indirect talks between Tehran and Washington to revive Iran's 2015 nuclear pact with world powers have stalled since September over a range of issues, including the Islamic Republic's violent crackdown on popular protests, Tehran's sale of drones to Russia and acceleration of its nuclear program.

Reporting by Reuters