The world grappled Sunday with the enormous implications after the United States inserted itself into Israel's war against Iran with an attack that raised urgent questions about what remained of Tehran’s nuclear program and how its weakened military might respond.

Iran lashed out at the US for crossing “a very big red line” with its risky decision to launch strikes on three Iranian nuclear sites.

Prior to the attack, Iran had threatened to retaliate against the U.S. if it became involved in its conflict with Israel.