Explosions were heard in southern Iran, in Qeshm Island, Bandar Abbas, and Sirik, according to reports from Iranian state media, Press TV on Wednesday morning.
Iranian state media reported several injuries after US forces have began launching "a series of powerful strikes against Iran to impose heavy costs for targeting and attacking commercial shipping crewed by innocent civilians in an international waterway," CENTCOM reported.
The semi-official Fars News Agency reported 10 explosions in Sirik and four in Mesen, on Qeshm Island early on Wednesday morning.
A US official told Reuters that the strikes targeted Iranian air defense systems, coastal surveillance, surface-to-air missiles, anti-ship cruise missiles, and drone launch sites.
The strikes on Wednesday were four or five times bigger in scope and power than the strikes 10 days ago, a US official told Axios.
US revoked the license that authorized Iranian oil sales
The Iranian Foreign Ministry condemned a US treasury move to revoke the temporary suspension of sanctions on Iranian oil sales, saying that Iran "holds the United States responsible for violating the memorandum of understanding, and will take any measures we deem necessary to safeguard our interests and national security."
Iran's foreign ministry added that "The US has repeatedly violated the terms of the memorandum of understanding over the past 20 days, either directly or through the actions of the Zionist entity against Lebanon."
On Tuesday the US revoked a general license that authorized the sale of Iranian oil, as a US official warned that Iran's actions in the Strait of Hormuz were "wholly unacceptable."
A source with knowledge of the attacks told The Jerusalem Post that Iran was responsible for launching at least five drones and missiles at three ships in the strait over the past day.
The US move came after three tankers reported being struck by unknown projectiles in and near the Strait of Hormuz in recent days, the British navy-affiliated agency UKMTO said in a report.
There was no immediate comment from Tehran or any claim of responsibility.
Reuters and Amichai Stein contributed to this report.