Crypto scammers are targeting the thousands of ships stranded near the Strait of Hormuz—and at least one ship that faced Iranian gunfire may have been tricked into believing it had paid Iran for safe passage.

The first warning of such a crypto scam came from the Greek maritime risk management company MARISKS on April 20, according to Reuters. The company alerted shipowners that scammers posing as Iranian authorities had sent messages to shipping companies asking for “transit fee” payments in bitcoin or tether.

That may be particularly confusing for shipping companies because of how Iran has asserted control over the Strait of Hormuz—a vital shipping channel and maritime chokepoint that normally allows Persian Gulf countries to provide one-fifth of the world’s oil and liquefied natural gas supply. Iranian authorities have demanded cryptocurrency payments from oil tankers to pass through the waterway and required ships to follow a route near Iran’s coastline to undergo inspection.

MARISKS identified one ship as having potentially fallen victim to crypto scams after it attempted to pass through the strait on April 18, although Reuters was unable to confirm that information. The incident supposedly occurred during a brief window when Iran claimed it was allowing ships to undergo inspection to pass through, but the ship in question turned back after Iranian military forces fired upon it. There are about 2,000 ships and 20,000 mariners still stranded near the strait.

That ship may not be alone in falling for a crypto scam while seeking safe passage. On April 22, the Liberia-flagged cargo ship Epaminondas, owned by the Greek company Technomar shipping and operated by the global shipping company MSC, was fired upon after it had reportedly received permission to pass through the strait, and authorities are checking whether the message purporting to grant safe passage “may have been fraudulent,” according to Ekathimerini.