Three American service members have been killed and five others seriously wounded during U.S. military operations against Iran, the U.S. Central Command said Sunday in what are the first announced U.S. casualties in the campaign, with additional personnel suffering minor injuries.

The United States launched massive bombardments against Iran and killed its supreme leader Saturday, with attacks ongoing Sunday.

"Three U.S. service members have been killed in action and five are seriously wounded as part of Operation Epic Fury. Several others sustained minor shrapnel injuries and concussions – and are in the process of being returned to duty," U.S. Central Command (CENTCOM) said in a statement.

"Major combat operations continue and our response effort is ongoing. The situation is fluid, so out of respect for the families, we will withhold additional information, including the identities of our fallen warriors, until 24 hours after next of kin have been notified," it added.

U.S. air and naval forces, together with Israeli forces, are heavily bombarding Iran and President Donald Trump has said the goal is to destroy the country's military capacity.