A senior US official said Israel had disabled Iranian missile defense systems

Israel knocked out three of Iran's Russian-made S-300 missile defense systems during its retaliatory strike against the Islamic Republic last week, Fox News has learned.

Israel carried out the strategic airstrike on October 26, marking a significant escalation in the conflict between the two countries during the operation's chosen name, “Days of Atonement.” The attacks targeted critical military infrastructure and represented both a symbolic and tactical blow to Iran's strategic capabilities after Tehran attacked Israel weeks earlier.

ISRAEL begins retaliatory strikes against Iran after rocket fire against Israelis

Israeli Air Force aircraft take off to attack Iran on October 26th. (IDF Spokesperson Unit)

The Biden administration was informed in advance of Israel's attack. The targets were chosen to send a targeted message to Iran and reduce its ability to fire ballistic missiles at Israel in the foreseeable future.

At the beginning of the year, Iran had only four S300 surface-to-air missile systems. In April, Israel shut down one of its missile systems in response to Iran's first ballistic missile attack. A senior US official confirmed that the airstrikes destroyed the three S-300 missile systems.

“Most of Iran's air defenses have been destroyed,” a senior Israeli official told Fox News.

On an internal call, Amos Hochstein, President Biden's Middle East adviser, said that “Iran is essentially naked” and no longer has missile defenses.

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A satellite image shows the Sharoud missile testing site, which was reportedly hit by Israel during its weekend attack on Iran. (INTELLITIMES)

Israeli warplanes also destroyed several radar systems needed to guide the same ballistic missiles fired at Israel in April and on October 1, when Iran fired 181 ballistic missiles at the Jewish state. Many of the missiles were destroyed before reaching their target, while others caused minimal damage, the Defense Ministry said.

Removing the radar systems will prevent Iran from firing these missiles in the future, a senior official said.

“Our message is very, very clear … 'Any threat, anywhere and at any time, we will know how to counter it, we will know how to strike,'” Israel Defense Forces Chief of Staff LTG Herzi Halevi said .

Halevi stressed that Israel had only deployed a portion of its capabilities and suggested further action could be taken if Iran escalated.

Defense Secretary Lloyd Austin has called on Iran not to respond to Israel's attacks.

Iranian air defenses were reportedly operating when Israel began attacking Iranian targets in Tehran. (Received from Fox News)

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“We believe this should be the end of this back and forth,” Pentagon deputy press secretary Sabrina Singh said during a meeting with reporters today. “We do not believe Iran should or must respond. On October 1, Iran fired the 200 ballistic missiles targeting civilian population centers. Israel’s response targeted military targets.”

“We see this as a way out,” she added.

Efrat Lachter of Fox News Digital contributed to this report.