Some 20 rockets were fired at Israeli military bases by Iranian forces in southern Syria just after midnight on Thursday, with some of the incoming missiles being intercepted by the Iron Dome defense system, the army said, amid sky high tensions on the northern border.

There were no reports of Israeli casualties in the attack. An army spokesperson said damage was caused to Israeli military bases, but that it was “limited.”

The Israeli army said the missile barrage was carried out by members of the Iranian Revolutionary Guard Corps’ Quds Forces. This appeared to be the first time that Israel attributed an attack directly to Iran, which generally operates through proxies. The late night rocket barrage was also the largest attack, in terms of the number of rockets fired, in the seven years of the Syrian civil war.

Get The Times of Israel's Daily Edition by email and never miss our top stories Free Sign Up

Tehran has repeatedly vowed revenge after the T-4 army base in Syria was struck in an air raid — widely attributed to Israel — on April 9, killing at least seven members of the IRGC, including a senior officer responsible for the group’s drone program. (Iran used the T-4 base to launch an attack drone carrying explosives into Israel in February; the drone was shot down.)

Immediately following the Iranian attack at 12:10 a.m., Syrian state media reported that Israeli artillery fire targeted a military post near the city of Baath in the Quneitra border region, where Syrian regime forces were stationed.

Approximately an hour and a half later, the Hezbollah-affiliated al-Manar news outlet reported that Syrian army air defenses were responding to an Israeli air strike against a target southwest of Damascus.

Syria’s state news agency said early Thursday that Syrian air defenses had intercepted “hostile Israeli missiles,” and Syrian media later said the missiles were fired over southwestern Damascus.

The pro-Syrian government Al-Mayadeen TV said more than 50 missiles had been fired from Syria toward Israeli forces in the Golan Heights.

The Israel Defense Forces spokesperson confirmed that the army had retaliated to the alleged Iranian attack, but would not comment on the specific details.

“The IDF sees this Iranian attack on Israel with severity,” said IDF spokesperson Lt. Col. Jonathan Conricus. “This event is not over,” he said.

Sirens blared across the Golan Heights throughout the exchange, sending residents into bomb shelters. The IDF Home Front Command called on residents to listen to security instructions as needed.

The spokesperson said the army was still sorting out many of the specific details related to the attack, such as which army bases were targeted, what types of projectiles were used, how many rockets were fired, from where they were launched, and how many were intercepted.

It was unclear if the Quds Forces’ rocket barrage would be the extent of Iran’s reprisal. Israeli intelligence assessments ahead of the attack indicated that Tehran was not looking to escalate the situation into all-out war and was looking instead for a contained way to retaliate, which may also be why the bombardment targeted military and not civilian sites.

A video shared on social media shortly after midnight on Thursday appeared to show the barrage of missiles apparently being fired by a multiple launch rocket systems, or MLRS, from Syria toward Israel.

Residents of both the Israeli and Syrian Golan Heights reported hearing loud, repeated explosions.

The attack came a day after the military called on local governments on the Golan Heights to open bomb shelters, in light of “abnormal” activities by Iranian forces in Syria. The barrage also followed US President Donald Trump’s announcement on Tuesday night that he was pulling the United States out of the Iran nuclear deal and reimposing sanctions on Tehran.

On Tuesday, eight Iranians were among 15 foreign pro-regime fighters killed in a suspected Israeli strike in Syria on a weapons depot of Iran’s elite Revolutionary Guards, a monitor said. The raid struck the area of Kisweh south of Damascus late Tuesday, the Britain-based Syrian Observatory for Human Rights monitoring group said on Wednesday.

Syria’s official news agency SANA said on Tuesday the army had intercepted two Israeli missiles fired toward Kisweh, with state television broadcasting images of fires in the nearby area.

Since the start of Syria’s civil war in 2011, Israel has repeatedly targeted positions of the Syrian army and the Lebanese Hezbollah terror group backing it inside the country.

On April 29, missile strikes — “probably Israeli” — fired on regime military positions near the cities of Hama and Aleppo in northern Syria killed at least 26 mostly Iranian fighters, according to the Observatory.

On April 9, missiles targeted the T-4 air base in the central province of Homs, killing up to 14 fighters, including seven Iranians, two days after an alleged chemical attack carried out by the Syrian regime.

Russia, Iran and Syria accused Israel of carrying out the strike.

In light of both the general tension and specific intelligence, the IDF went on high alert this week, deploying additional missile defense batteries in northern Israel. “There is high preparedness of IDF troops for an attack,” the army said on Tuesday.

A number of army reservists were called upon Tuesday night, the army said. An IDF spokesperson would not elaborate on which units they came from, but media reports indicated they served in air defense, intelligence and Home Front Command units.

Earlier on Tuesday, the US embassy in Israel also prohibited American government employees from visiting the Golan Heights without approval in light of the security situation on the border.

“The IDF is ready and prepared for a variety of scenarios and warns that any action against Israel will be answered with a fierce retaliation,” the army said.

On Sunday night, Israeli defense officials warned that Iran was planning to retaliate for recent deadly airstrikes in Syria, which have been attributed to the Jewish state, by having its proxies fire missiles at military targets in northern Israel sometime in the near future.

Security forces were also preparing for the possibility of attempted infiltrations of military bases and communities in the north, Hadashot TV news reported on Monday.

Agencies contributed to this report.