This was the day that President Biden and his team had feared for more than three months, the day that relatively low-level attacks by Iranian proxy groups on American troops in the Middle East turned deadly and intensified the pressure on the president to respond in kind. With three American service members killed and two dozen more injured by a drone in Jordan, Mr. Biden must decide how far he is willing to go in terms of retaliation at the risk of a wider war that he has sought to avoid ever since the Oct. 7 terrorist attack by Hamas touched off the current Middle East crisis. Until now, the president had carefully calibrated his responses to the more than 150 attacks by Iranian-backed militias on American forces in the region since Oct. 7. He essentially ignored the majority that were successfully intercepted or did little to no damage while authorizing limited U.S. strikes focused mainly on buildings, weapons and infrastructure after attacks that were more brazen, most notably against the Houthis in Yemen who have targeted shipping in the Red Sea. The first deaths of American troops under fire, however, will require a different level of response, American officials said, and the president's advisers were in consensus about that as they consulted with him by secure videoconference on Sunday.

The Pentagon placed 2,000 U.S. troops on a 24-hour notice to deploy. U.S. forces in western Iraq were targeted in another drone attack early Tuesday morning, according to a report, marking the latest in a string of assaults on American troops in the Middle East as the Israel-Hamas war continues. Two armed drones were used against Iraq's Ain al-Asad airbase, Reuters reported, citing a security source and a government source. The base hosts international troops that assist Iraq in defeating a terror group called the Daesh, or the Islamic State. No casualties or damage were reported.