"Listen to the American people. Follow the Constitution," said Just Foreign Policy. "End these illegal and unauthorized hostilities against Iran. NOW."

The strikes were in response to what it said were Iranian attacks on three commercial vessels that were transiting the waterway, US Central Command said.

The US strikes targeted Iranian air-defence systems, coastal-surveillance systems, surface-to-air missiles, anti-ship cruise missiles and drone-launch sites, a US official said.

The United States launched a series of strikes against Iranian targets early Wednesday after three merchant ships were struck in waters off Oman.