Iran has full control of the Gulf and the Strait of Hormuz, the head of the Revolutionary Guards navy, General Alireza Tangsiri, said Monday, according to the Tasnim news agency.
Iranian officials have in the past threatened to block the Strait of Hormuz, a major oil shipping route, in retaliation for any hostile U.S. action.
Tension between Iran and the United States has escalated since President Donald Trump pulled out of a 2015 nuclear deal between Iran and world powers in May and reimposed sanctions.
Senior U.S. officials have said they aim to reduce Iran's oil exports to zero.
Iran's Supreme Leader Ayatollah Ali Khamenei, the most senior authority in the Islamic Republic, said last month that he supports the idea that if Iran is not allowed to export oil then no country in the region will be allowed to export oil from the Gulf.