TEL AVIV — Israel has carried out a military strike inside Iran, a US official told CNN Friday, the latest move in a dangerous escalation that threatens to push the already volatile region into all-out war.

The US was given advance notification Thursday of an intended Israeli strike in the coming days, but did not endorse the response, the senior US official said.

Iran’s air defense systems were activated in several locations after three explosions were heard close to a major military airbase near the Iranian city of Isfahan, state media reported early Friday morning. Iran’s semi-official FARS news agency said fighter jets were located at the airbase and that a military radar was a possible target.

Multiple state-aligned news agencies reported that sites associated with Iran’s nuclear program were “completely secure” and the attack appeared to be limited in scope.

“Following the activation of air defense in some parts of the country to deal with some possible targets, reports indicate that so far, no large-scale strikes or explosions caused by any air threat has been reported,” Iranian state-run media reported.

Reports of Friday’s strike came hours after Iran’s Foreign Minister Hossein Amir-Abdollahian told CNN that if Israel takes any further military action against Iran, its response would be “immediate and at a maximum level.”

“If the Israeli regime commits the grave error once again our response will be decisive, definitive and regretful for them,” he added, noting that this warning had been communicated to the White House via the Swiss Embassy in Tehran.

Tensions across the Middle East remain on a knife edge, following Iran’s unprecedented direct strike against Israel late Saturday. The attack, during which Iran launched more than 300 drones and cruise missiles toward Israel, came in response to a suspected Israeli strike on an Iranian diplomatic complex in the Syrian capital, Damascus, on 1 April, which killed a top commander, and several others.

Outgoing flights from several Iranian airports were briefly canceled or suspended early Friday but aviation authorities later lifted all restrictions.

Iran’s National Cyberspace center spokesperson Hossein Dalirian said on X that three drones “have been successfully shot down by the country’s air defense, there are no reports of a missile attack for now.”

Senior Iranian military commander Second Brigadier General Mihandoust said the sound of a loud explosion near Isfahan was caused by “air defense firing at a suspicious object” and that there was no “damage or incident,” according to the state-aligned Tasnim news agency.

The Israeli military said they “don’t have a comment at this time,” when asked by CNN about reports of explosions in Iran.

Israel’s action in Iran is the latest escalatory move in a region that has been rocked by Israel’s devastating war in Gaza following Hamas’ brutal October 7 attack. That attack killed more than 1,200 people, mostly civilians, and saw more than 200 others taken hostage.

Israel’s bombardment and siege of Gaza has killed more than 33,000 Palestinians, according to Palestinian officials, caused widespread destruction of the enclave and sparked a humanitarian crisis where more than 1 million people face ‘catastrophic’ levels of hunger.

Prior to Friday’s Israeli strike, the US expectation was the country would not target Iran’s civilian or nuclear facilities, another senior US official told CNN.

CNN has previously reported that Israel told the US its response would be limited in scope. US intelligence had suggested Israel was weighing a narrow and limited strike inside Iran because they feel like they have to respond with a kinetic action of some kind given the unprecedented scale of the Iranian attack.

The range of targets was “never specified in precise terms but nuclear and civilian locations were clearly not in that category,” the second official added.

Israel’s Western allies have both rallied to its defense in the wake of Iran’s attack Saturday, while also urging restraint.

Biden told Israeli Prime Minister Benjamin Netanyahu he should consider Iran’s strikes a win, since they had been largely unsuccessful and demonstrated Israel’s ability to defend itself.

Biden had already made clear to Netanyahu that the US would not participate in any offensive operations against Iran in response, a senior administration previously told CNN.

Benny Gantz, a key member of Israel’s war cabinet, had pushed for a swift response to the attack, two Israeli officials told CNN, arguing that the longer Israeli delayed its response, the harder it would be to garner international support for it.

Some hardline officials have gone further. Israeli National Security Minister Itamar Ben Gvir said Israel should “go crazy” in response.

Arab states, including those that are friendly with Israel, have expressed concern about a potential escalation from Iran’s attack, but haven’t outright condemned it. — CNN