March 2 (UPI) — More than 550 people have been killed in the joint strikes by the United States and Israel, Iran’s Red Crescent said Monday.

Thousands of targets within Iran’s borders have been hit as the United States and Israel continue to expand the scope of their attacks. As of Monday morning, Israel has begun strikes on Hezbollah targets in Lebanon, the Israel Defense Force said.

Lebanese Prime Minister Nawaf Salam said in a statement that any military activities launched by Hezbollah are “illegal.”

During a press conference on Monday morning, U.S. Secretary of Defense Pete Hegseth said there are not U.S. troops on the ground but did not rule out sending ground forces to war.

The defense secretary called the strikes “the most lethal and precise air power campaign in history.” The attacks include the use of B-2 stealth bombers, missiles, drones and classified weapons.

“All on our terms with maximum authorities. No stupid rules of engagement, no nation building quagmire, no democracy building exercise, no politically correct wars,” Hegseth said. “We fight to win and we don’t waste time or lives.”

Hegseth echoed President Donald Trump’s comments over the weekend, saying there will be casualties. U.S. Central Command posted on social media that four U.S. troops have been killed in action.

U.S. Gen. Dan Caine said during Monday’s press conference that he expects more losses of U.S. troops to come.

“This is not a single, overnight operation,” Caine said. “The objectives CENTCOM has been tasked with will be difficult and gritty work. We expect to take additional losses.”

Hegseth described the impetus for the attacks as the result of a “one-sided war” against America by Iran.

“We didn’t start this war but under President [Donald] Trump we are finishing it,” Hegseth said. “Their war on Americans has become our retribution against their ayatollah and his death cult.”

Hegseth added that Iran’s development of nuclear capabilities, ballistic missiles and drones were “no longer a tolerable risk.”

Hegseth disputed that the attacks are part of a “regime change war,” after the death of Ayatollah Ali Khamenei, announced Saturday.