The Israeli military on Friday acknowledged that it attacked the T-4 air base in central Syria last month — killing at least seven Iranian revolutionary guards — as well as its ongoing intelligence and air campaign to prevent Tehran from carrying out reprisals for the strike.

The preemptive effort by the Israel Defense Forces is known collectively as “Operation Chess.”

Until now, Jerusalem has officially remained mum on the April 9 attack, which was quickly attributed to Israel by Iran, Syria, Russia and anonymous US officials.

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According to the army, the specific target of the strike on the T-4 base was a shipment of advanced air defense weapons, including one with a range of 110 kilometers (70 miles). This appeared to confirm a Wall Street Journal report from April 18, which said a modern anti-aircraft system was hit in the attack, though not necessarily the same model.

Tehran has repeatedly vowed revenge after the T-4 base was struck in the Israeli air raid, killing at least seven members of the Iranian Revolutionary Guard Crops, 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, according to the IDF; the drone was shot down.

According to IDF assessments, in recent weeks Iran has stepped up its efforts to bring a number of advanced munitions into Syria, notably air defense systems, with which the IRGC could fire on Israeli fighter jets.

The anti-aircraft systems Iran has been bringing into Syria are meant to threaten Israel’s air superiority in the region, providing a cover for Iranian forces in Syria to carry out attacks against the Jewish state, the military believes.

Out of concerns that these weapons might be targeted by Israel, Iranian forces have been moving them around and hiding them in Syria, the army said.

The decision to attack those Iranian anti-aircraft systems was adopted by the IDF with the knowledge that striking them would likely result in Iranian fatalities, which could further spur Tehran’s desire for reprisals.

The Britain-based Syrian Observatory for Human Rights said at least 23 fighters were killed in the Israeli strikes, including 18 foreigners.

Tehran’s efforts, led by the commander of the IRGC’s al-Quds force Qassem Soleimani, to bring in its own equipment and carry out its own attacks against Israel is derived from an understanding that Iran is losing some of its support in Syria, as dictator Bashar Assad focuses on conquering the last of the rebel-held areas in his country and the Hezbollah terrorist group seeks to stop being an “Iranian puppet,” according to IDF assessments.

Since the T-4 attack, Iran has been looking for a way to retaliate, specifically by launching missiles or rockets at Israeli military positions in northern Israel to kill or injure IDF soldiers, according to Israeli intelligence assessments leaked to the press on Sunday. By focusing on military targets, Iran likely hoped to avoid a larger confrontation, as would happen if Israeli civilians were killed.

Iran carried out its revenge — in almost exactly the way predicted by Israeli intelligence — just after midnight on Thursday, launching some 20 rockets at IDF positions along the Golan border.

According to the army, four of those rockets were shot down by the Iron Dome missile defense system and the rest failed to clear the border.

Nevertheless, the army believes that the Iranian people are convinced that the attack was a resounding success and that Israel’s censor is preventing news outlets from reporting on the extensive damage. This line of reasoning can be seen expressed in some pro-Iranian and Persian-language news outlets.

Ahead of the attack, Israeli officials repeatedly made clear that they would not tolerate any Iranian retaliatory strike and would fight to prevent it.

“If someone tries to carry out an attack against the State of Israel, to fire rockets against the State of Israel, we will always try to preempt them,” Defense Minister Avigdor Liberman said again on Friday.

In response to the rocket attack, over the course of less than two pre-dawn hours, Israeli F-15 and F-16 fighter jets dropped “many dozens” of bombs on more than 50 Iranian targets throughout Syria, evading “dozens of missiles” in an effort to severely set back Tehran’s entrenchment in Syria.

The mission — the largest air campaign carried out by Israel in Syria in over 40 years — received its own designation: “Operation House of Cards.”

While some in the political upper echelon called for an even more aggressive attack against Iranian positions in Syria, the army’s recommendations for a pinpoint, limited strike, with the goal of targeting Iranian infrastructure rather than troops, was ultimately adopted by the security cabinet.

According to Israeli assessments, there are between 1,000 to 2,000 Iranian troops in Syria, most of them acting in an advisory capacity to local Tehran-backed Shiite militias.

Though the army generally took responsibility for conducting preemptive airstrikes in Syria as part of “Operation Chess,” it refrained from acknowledging specific attacks.

According to the Syrian Observatory for Human Rights, on Tuesday night, a missile launcher belonging to pro-Iranian forces was hit by an airstrike in el-Kiswah, south of Damascus. The attack reportedly killed nine pro-Iranian fighters.

Portions of el-Kiswah, an area previously identified as a base for Iranian forces, were later flattened by the Israeli Air Force during its strikes on Thursday.

On April 29, missile strikes also hit regime military positions outside Aleppo and Hama, in northern Syria, reportedly killing at least 26 fighters, mostly Iranians.

A pro-regime official later told The New York Times that the air raids destroyed some 200 missiles.

Until now, Iranian positions in Syria have mostly been defended by dictator Bashar Assad’s anti-aircraft batteries.

With the exception of one fallen Israeli F-16 fighter jet — which the air force blames on misjudgment by the pilot — the Syrian air defenses have been largely ineffective to prevent Israeli strikes.

On Thursday night, Fox News reported that Iranian forces in Syria did not ask the Syrian government, or even notify Syrian leaders, before launching its 20 missiles at Israel.

“It appears that the regime of Bashar Assad of Syria wants to distance itself from Iran’s military activity in its very own back yard,” Fox News’s David Lee Miller reported from the Golan Heights.

Iran’s proxy Hezbollah also does not appear to be particularly keen on joining the immediate fight against Israel, as it regroups following its extended fighting in the Syrian civil war on behalf of Assad, and in light of its deepening involvement in domestic Lebanese politics, especially following last week’s parliamentary elections.

Despite this, the well-armed and well-trained terror group, which is believed to have an arsenal of more than 100,000 missiles and rockets, remains an important Iranian asset and the Israeli military believes there is a chance the fight with Tehran could spread to Lebanon as well, a senior air defense officer said on Thursday.

Russia also appeared to be distancing itself from Iran.

Sources told Saudi-owned Asharq Al-Awsat newspaper that Deputy Russian Foreign Minister Sergei Ryabkov warned his Iranian counterpart Abbas Araghchi in Tehran on Wednesday against carrying out a strike against Israel, as Jerusalem would respond to any attack.

A senior Israel Air Force officer told reporters that Thursday’s air raids were coordinated with Russia.

“We told the Russians that we were going to strike in Syria, but we didn’t tell them where we exactly were striking or what the targets were,” the officer said.

Since large numbers of Russian forces arrived in Syria in 2015, Jerusalem and Moscow have maintained a so-called “mechanism” to ensure that the two countries keep out of each other’s way in the war-torn country.

“The mechanism worked to its fullest and we preserved our freedom of operation,” the air force officer said.