Israel’s military carried out strikes against Iranian targets in Syria after it said Iranian forces based there fired rockets at its soldiers in the Golan Heights, raising the risk of a wider regional war just a day after President Donald Trumpwithdrew the U.S. from the international nuclear deal with Tehran.

Iran’s attack in the Golan appears to be the first time Iran has opened fire from Syria on Israeli targets. The Israeli military said dozens of Iranian military sites across southern and central Syria were struck. The Israeli military called the strikes—which focused on sites related to logistics, intelligence and ammunition storage—its largest-ever operation against Iranian positions in Syria.

“It will take substantial time for the Iranians to replenish these systems,” said Jonathan Conricus, an Israeli military spokesman.

In a separate incident, Iran-backed Houthi rebels in Yemen fired a barrage of missiles into Saudi Arabia on Wednesday. The pair of attacks were an early indication that Iran and its allies are flexing their muscles in the Middle East after Washington’s move.

The strikes heightened tensions in a region already on edge and underlined the risk of direct confrontation between Iran and Israel following the U.S. exit from the nuclear agreement. Iran, until now, had held back from any retaliatory response to recent Israeli strikes on its assets in Syria.