Photo: Ali Mohammadi/Bloomberg

A small oil tanker from the United Arab Emirates travelling through the Strait of Hormuz entered Iranian waters and turned off its tracker two days ago, leading the U.S. to suspect Iran seized the vessel amid heightened tensions in the region, an American defence official said Tuesday.

Iran's foreign ministry spokesperson acknowledged on Tuesday that the Iranian navy came to the aid of a disabled tanker in the Persian Gulf that needed repairs.

"An international oil tanker was in trouble due to a technical fault in the Persian Gulf," spokesman Abbas Mousavi told the semi-official news agency ISNA.

"After receiving a request for assistance, Iranian forces approached it and used a tugboat to pull it towards Iranian waters for the necessary repairs to be carried out," he said, without acknowledging that the vessel in question was the oil tanker Riah, which disappeared from official tracking screens on Saturday evening after turning off its transponder.

The vessel has made numerous short oil trips ferrying cargo around the region prior to its virtual disappearance.

Officials from the United Arab Emirates, which had been the home base of the vessel in recent months, acknowledge the ship sent out no distress call — something that likely would have happened if it ran into mechanical issues.

Oil tankers previously have been targetted in the wider region amid tensions between the U.S. and Iran over its unravelling nuclear deal with world powers.

The concern about the Riah comes as Iran continues its own high-pressure campaign over its nuclear program after U.S. President Donald Trump unilaterally withdrew America from the accord over a year ago.

Recently, Iran has inched its uranium production and enrichment over the limits of its 2015 nuclear deal, trying to put more pressure on Europe to offer it better terms and allow it to sell its crude oil abroad.

However, those tensions also have seen the U.S. send thousands of additional troops, nuclear-capable B-52 bombers and advanced fighter jets into the Mideast. Mysterious attacks on oil tankers and Iran shooting down a U.S. military surveillance drone has added to the fears of an armed conflict breaking out.

The Riah, a 58-meter oil tanker, typically made trips from Dubai and Sharjah on the UAE's west coast before going through the strait and heading to Fujairah on the UAE's east coast. However, something happened to the vessel after 11 p.m. on Saturday, according to tracking data.

VNF/CBC