As Israeli Prime Minister Benjamin Netanyahu vowed to fight “as long as it takes,” Iran fired missiles at Israel, and Israeli warplanes attacked air defenses around Tehran.

The United States is the main international backer of Israel, Iran's biggest regional foe. It is also a close ally of Sunni Gulf monarchies which for years pursued their own rivalry with the Islamic Republic, seeing it as their main regional threat.

Iran and Israel exchanged more airstrikes overnight Friday and continuing late Saturday after Israel mainly attacked Iranian nuclear and military targets two days ago.

Iranian officials have repeatedly denied seeking a nuclear weapon. The United States and Iran have held five rounds of negotiations toward achieving an agreement that would limit Iran's nuclear activities in exchange for sanctions relief, with a sixth round of talks scheduled for Sunday.

Iran's top diplomat Abbas Araghchi said Saturday that Israel's strikes on his country were undermining nuclear talks with the United States. Araghchi, in a call with Russia's Foreign Minister Sergei Lavrov,

The United States has pulled some diplomatic staff and military families out of the Middle East, citing unspecified regional security risks.

Israel’s leader and President Trump appeared to bet they can persevere, but other world leaders warned of unintended outcomes in a volatile region.

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.