Iran says it has helped a foreign oil tanker in the Strait of Hormuz amid U.S. concern that Tehran seized the vessel.
Iranian Foreign Ministry spokesman Abbas Musavi said on July 17 that the country towed an unnamed vessel to harbor after it suffered a technical malfunction.
But the United States said that the vessel had not been in contact with its owner in the United Arab Emirates since its transponder turned off on July 13.
TankerTrackers, an online oil-shipment tracking service, named the vessel as the U.A.E. tanker MT Riah. It said the tanker crossed into Iranian waters on July 14.
The tanker's last known position was off Qeshm Island in the Strait of Hormuz, it said.
A U.S. defense official told AP that Washington "has suspicions" that Iran seized the vessel.
The incident comes amid tensions between Tehran and Washington.
Britain seized an Iranian tanker off the coast of Gibraltar on July 4 over suspicions it was breaking sanctions by taking oil to Syria.
Iran has called for London to release the tanker and has threatened to seize British ships in retaliation.