Donald Trump threatened further strikes on Kharg Island, after claiming U.S. strikes Friday had "totally demolished" much of the island.
Speaking to NBC News Saturday, the U.S. President said: "We may hit it a few more times just for fun."
The remarks marked a sharp escalation from Trump, who had previously said the U.S. was targeting only military sites on Kharg and dealt a blow to diplomatic efforts.
His administration has brushed aside attempts by Middle Eastern allies to open talks, three sources told Reuters, as the conflict grows.
Iranian Foreign Minister Abbas Aragchi, in response, said Iran would respond to any attack on its energy facilities.
