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.

The move, the first time the U.S. has attacked Iran, is a major escalation of the conflict between Israel and Iran.

The United States has attacked three sites in Iran, inserting itself into Israel’s war aimed at destroying the country’s nuclear program in a risky gambit to weaken a longtime foe that prompted fears of a wider regional conflict.