Israel unleashed airstrikes across Iran for a third day and threatened even greater force as some Iranian missiles evaded Israeli air defenses to strike buildings in the heart of the country.

National security experts warn that Israel's attack on Iran shows why Chinese land and asset purchases in the U.S. pose a significant threat to American security.

The U.S. says it wasn't involved in the strikes on Iran, but three American officials told NBC News the U.S. is assisting in shooting down Iranian missiles and projectiles targeting Israel.