Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, acknowledged the possibility of an extended campaign, as the military announced that six U.S. service members had been killed so far.

Americans in Riyadh and other cities were advised to shelter in place immediately.

The secretary of state signaled that an escalation in Iran was likely and said the attacks underway were both pre-emptive and defensive, describing a far more extensive mission than was initially laid out.

Much of Tehran’s arsenal of missiles may be hidden underground, making it harder to destroy.

The wars in Afghanistan and Iraq offered a stark lesson in the limits of military force. The Iran attacks suggest an era of postwar wariness is over.

The Middle East is facing deaths and destruction as Iran retaliates against a huge American-Israeli military campaign.

Separately, a drone attack hit the U.S. Embassy compound in the Persian Gulf state, as Iran continues to target American assets across the Middle East.

The United States and Israel started a war with Iran by killing its supreme leader, Ayatollah Ali Khamenei.

Emirates and FlyDubai said they were making a small number of flights to and from Dubai starting Monday night after shutting down because of airstrikes in the region.