The Biden administration was made aware of Israel’s plans to strike Iran in retaliation for the Oct. 1 ballistic missile attack days in advance of the strike Friday night. 

A source familiar with the proceeding confirmed to Fox News that multiple conversations were held between U.S. and Israeli officials, and the exact time of attack was communicated to Washington on Friday. 

Speculation surfaced earlier in the day that the long-awaited attack – which Israel vowed to hit Tehran with immediately following the Oct. 1 attack – was imminent given the announcement by U.S. Central Command confirming the deployment of more F-16’s to the region. 

ISRAEL BEGINS RETALIATORY STRIKES AGAINST IRAN FOLLOWING MISSILE BARRAGE TARGETING ISRAELIS

White House National Security Council (NSC) communications director John Kirby would not confirm whether the reinforcement of U.S. defenses in the region signified that an Israeli-led attack was forthcoming, but said it showed an "ironclad" commitment to Jerusalem. 

Following Israel’s strikes on Iran early Saturday morning local time under a mission dubbed "Days of Repentance," NSC spokesman Sean Savett confirmed the operation had begun "against military targets in Iran as an exercise of self-defense and in response to Iran’s ballistic missile attack against Israel on Oct. 1."

Roughly three hours after the Israeli attack started – in which some 140 Air Force planes were reportedly sent to the skies for the assault, according to Israeli local news outlet Channel 12 – the Israel Defense Forces (IDF) announced the operation was "completed."

"The retaliatory strike has been completed and the mission was fulfilled," the IDF said in a statement." "Our planes have safely returned home." 

IDF Spokesperson, Rear Admiral Daniel Hagari addressed Iran directly in a statement once the mission was over. "If the regime in Iran were to make the mistake of beginning a new round of escalation — we will be obligated to respond."

He continued, "Our message is clear: All those who threaten the State of Israel and seek to drag the region into a wider escalation — will pay a heavy price.

We demonstrated today that we have both the capability and the resolve to act decisively — and we are prepared — on offense and defense — to defend the State of Israel and the people of Israel," Hagari concluded.

Strikes on military bases in Syria and Iraq were also reported Friday by Israeli news outlets, though the IDF did not mention these locations in their release. 

US REINFORCES CENTRAL COMMAND WITH FRESH SUPPLY OF F-16S IN 'IRONCLAD' COMMITMENT TO DEFEND ISRAEL

Senior Israeli defense source told Fox News Digital the targets of the attack were "solely military and intelligence targets."

Iranian news outlet Tasnim news agency, which has known ties to the Iranian Revolutionary Guard Corps (IRGC), cited a senior source who said, "We reserve the right to respond to any attack."

"Israel will undoubtedly receive a proportional response to any action," the source added, suggesting the aggressive volley between Israel and Iran will continue. 

Neither U.S. nor Israeli officials have yet commented on the effectiveness of Israel’s strikes, though local Israeli news outlet Channel 12 reported that Iran’s air defense system had been damaged.

The IRGC headquarters in Tehran was also reported to have allegedly been hit by strikes, though Fox News has not been able to independently verify this. 

Al-Mayadeen channel, a Lebanese pro-Hezbollah and Iran-aligned network, claimed, "Air defense systems intercepted all hostile targets in Tehran. Israel’s attempt to strike air defense bases around Tehran has failed."

The IDF said its Air Force "struck missile manufacturing facilities used to produce the missiles that Iran fired at the State of Israel over the last year." 

"These missiles posed a direct and immediate threat to the citizens of the State of Israel," the IDF added. "Simultaneously, the IDF struck surface-to-air missile arrays and additional Iranian aerial capabilities, that were intended to restrict Israel's aerial freedom of operation in Iran."