The leader of Lebanon’s Hezbollah group said on Monday a missile salvo into the Israeli-occupied Golan Heights last week marked a new phase in the Syrian war and showed Damascus and its allies would not let Israeli attacks in Syria go unanswered.

Israel has said the attack from Syrian territory was carried out by Iran’s Revolutionary Guards, which set up Shiite Hezbollah in Lebanon in 1982. Iranian forces and Hezbollah have deployed to Syria in support of President Bashar Assad.

Israel said it had attacked nearly all of Iran’s military infrastructure in Syria in response to the attack, which marked the first time Iranian forces have fired at Israeli-held territory. It was the most extensive military exchange ever between the foes.

Hezbollah leader Sayyed Hassan Nasrallah, in a televised speech, said 55 missiles were fired in the attack last Thursday — nearly three times more than the 20 missiles which Israel said were shot down or had not reached their targets in the attack.

He did not say if Hezbollah had taken part in the attack.

“The message delivered … is that neither the Syrian leadership, nor the Syrian army, nor the Syrian people, nor the allies of Syria will allow Syria to remain exposed to Israeli attacks and they are ready to go to the furthest extent,” Nasrallah said.

Israel had tried to disguise the scale of the attack, he said. The rocket attack had set the stage for “an entirely new phase,” he said.

Israel, which fears Iran and Hezbollah are turning Syria into a new front against it, has struck targets in the country many times during the war, hitting the Syrian army, Hezbollah and what it has characterized as Iran-backed positions.

Ahead of last week’s attack, Iran had vowed to respond to an Israeli attack, which it said had killed seven of its military personnel at a Syrian air base in April.

Addressing Israel, Nasrallah said: “If you thought that you could kill and bomb without receiving a response, then you are wrong and misguided, and the response will be in the appropriate form and time.”

Israel said the attack was carried out by the Quds Force, an external arm of Iran’s Revolutionary Guards. The White House said Iran’s deployment of offensive rocket and missile systems in Syria aimed at Israel was “an unacceptable and highly dangerous development for the entire Middle East.

Nasrallah said Israel had not struck strategically significant targets during its attacks in Syria.

He added that a message had been delivered to Israel via an international party that if it crossed “red lines” then the “next bombardment would be in the heart of occupied Palestine.

He was referring to Israel’s borders on the eve of the 1967 war. Nasrallah did not spell out what the “red lines” were.

Earlier on Monday, Nasrallah’s deputy, Sheikh Naim Qassem, said the attack had affirmed “the balance of deterrence” between Israel and its adversaries.