Oman and Qatar were leading efforts to begin ceasefire talks, while mediators said Iran was open to resuming nuclear negotiations if Israel’s attacks stop.

Some of Israel’s attack was televised. On Monday evening, an Iranian state news anchor was live on air when an explosion shook the scene, causing falling debris and the sound of screams and breaking glass. Iranian state media said the blast injured some employees, disabled its website and forced the broadcaster briefly off air.

Iran has vowed to retaliate against the U.S., too, while Trump has warned: “If we are attacked in any way, shape, or form by Iran, the full strength and might of the U.S. Armed Forces will come down on you at levels never seen before.” Here’s what to know about U.S. involvement so far.