DUBAI, United Arab Emirates (AP) — The U.S. Navy's Mideast-based 5th Fleet said Friday it was “looking into” reports that Iran had seized two Greek oil tankers after Tehran threatened to take “punitive action” against Athens over a seizure of one of its tankers.

Cmdr. Timothy Hawkins of the 5th Fleet told The Associated Press that the Navy was continuing to investigate. He did not elaborate.

Iran's Nour News website, close to its security services, made the threat just as shipping news site Lloyd's List said it believed two Greek tankers had been seized in the Persian Gulf.