WASHINGTON, July 7 (Reuters) - The U.S. military has launched a series of strikes against Iran, U.S. Central Command said Tuesday, adding that the strikes were in response to what it said were Iranian attacks on three commercial vessels that were transiting the Strait of Hormuz. "U.S. Central Command forces have begun launching a series of powerful strikes against Iran to impose heavy costs for targeting and attacking commercial shipping," a U.S. military statement said.