Iran on Saturday launched 300 drones and missiles at Israel, nearly all of which were thwarted by Israel, U.S. and allied forces.

Iran’s Islamic Revolutionary Guards Corps said it launched 300 drones and missiles at Israel on Saturday from Iran and the locations of its regional proxies, in an attack that could lead to a major escalation between the regional archenemies.

Israel, the U.S. and allied forces intercepted 99 percent of the projectiles fired by Iran, Israel said.

The attack marks the first time that Iran has ever launched a direct military assault on Israel. Iran said the attack was in response to a suspected Israeli strike on an Iranian diplomatic building in Syria in early April.