Iranian state TV on Wednesday claimed that Iran had foiled an attempt by the US to "steal" oil in the Sea of Oman.
According to Iran's Mehr news agency, there was a confrontation between speedboats belonging to the Iranian Revolutionary Guards and a US ship.
The US ship left the scene, Mehr said, promising that footage would soon follow.
According to Press TV, US forces used helicopters and warships in order to block an oil tanker, but their attempts failed. Press TV also said that the Iranian tanker returned to Iran's territorial waters.
Fars reported that the Iranian government is working to ensure the safety of Iranian vessels in the Persian Gulf.
According to Reuters, the Iranian vessels foiled an attempt by the US to take control of an oil tanker in the Sea of Oman. The oil ship was brought to Iran's territorial waters, the report said.
In August, Iran attacked an Israeli-owned oil tanker, the MV Mercer Street, as it sailed in the Arabian Sea. Two of the ship's crew members were killed in that attack, which the US promised to repay with an "appropriate response."