TEHRAN, June 10 (Xinhua) -- A number of explosions were heard early Wednesday and air defenses were activated in the port city of Bandar Abbas, Qeshm Island, Sirik County and Jask County in southern Iran, state-run IRIB TV reported, citing sources.

The semi-official Tasnim news agency reported that six explosions were heard in Sirik, Qeshm Island and the southern city of Minab, adding that areas in the three regions were attacked by U.S. fighter jets.

The explosions came as U.S. Central Command said in a post on social media platform X that its "forces began launching self-defense strikes against Iran at 5 p.m. ET today at the Commander in Chief's direction, in response to yesterday's downing of a U.S. Army Apache helicopter."

"The mission is a proportional response to unjustified Iranian aggression," it added.

U.S. President Donald Trump on Tuesday accused Iran of shooting down a U.S. Army helicopter near the Strait of Hormuz and vowed to respond.

The two pilots aboard the helicopter were rescued and are "safe and uninjured," Trump said.

"Nevertheless, the United States must, of necessity, respond to this attack," he added.