The U.S. launched airstrikes on Iran's Revolutionary Guard Sunday in retaliation for the killing of American troops in Jordan, escalating the conflict after efforts to restore a truce collapsed.

The strikes are part of a weeklong campaign that began with a struggle over control of the Strait of Hormuz and has seen Iran strike U.S.-allied countries across the Middle East.

The U.S. has targeted bridges, electrical facilities and other targets in Iran and Tehran has retaliated by hitting power and desalination plants in Kuwait, threatening daily life in that small, oil-rich desert nation.

Iran also has stepped up its threats to further expand the strikes, drawing a warning overnight from the United Arab Emirates.

Kuwait and Bahrain again activated air defenses Sunday morning as they warned of incoming Iranian drones and missiles.