DUBAI, United Arab Emirates -- Maritime security firms say a suspicious object has been found on the hull of an oil tanker in the Persian Gulf off the coast of Iraq.

The firms say officials fear it could be a limpet mine on the MT Pola, though the Liberian-flagged tanker was receiving assistance Thursday in the Persian Gulf off Basra.

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The two firms, Ambrey Intelligence and Dryad Global, say investigations are ongoing.

The United Kingdom Marine Trade Operations, an organization under Britain’s royal navy, says it is "aware of an ongoing situation" there, without elaborating.

The U.S. Navy's 5th Fleet, which patrols the Mideast, did not immediately respond to a request for comment.

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The incident comes amid heightened tensions between Iran and the U.S. In 2019, the U.S. blamed Iran for a series of limpet mine attacks on oil tankers near the Strait of Hormuz, the narrow mouth of the Persian Gulf through which 20% of all the world's oil passes. Iran denies being involved.