A top commander in Iran’s Revolutionary Guard was killed among several others in an airstrike on the country’s consulate building in Damascus, Syria, according to Iranian officials and state-affiliated media, which blamed Israel for the attack.

Iran’s Foreign Ministry said that senior Islamic Revolutionary Guard Corp (IRCG) commander Mohammed Reza Zahedi was killed in the attack.

People gathered around the flattened building in Syria’s capital, according to photographs of the scene. Footage of the aftermath of the blast, published by Iranian state media Press TV, showed extensive damage, fire and smoke at the scene.

Speaking on camera to reporters in Damascus, Iranian ambassador Hossein Akbari alleged that the consulate building, located next to the Iranian embassy, “was targeted with six missiles from Israeli F-35 warplanes.”

“Between five and seven people were killed in the attack. I was in my office in the embassy at the time and witnessed the destruction myself,” Akbari said.

Iranian embassy staff and military advisers were among the dead, he said. In a separate interview, Akbari added that two Syrian policemen are also among the injured. CNN cannot independently verify the claims or casualty figures.

The attack “is perhaps the first time that the Zionist regime allows itself to attack an official building of the Islamic Republic of Iran embassy, which had the flag of the Islamic Republic raised on top of it,” according to Akbari, who described the strike as “against all international laws.”

Asked for comment on the incident by CNN, the Israel Defense Forces said it does not comment on foreign reports.

CNN has geolocated images and video on social media showing smoke rising from the consulate building next to the embassy, with fire engines visible at the scene.

Iran’s foreign ministry spokesman, Nasser Kanaani, warned of possible “reciprocal measures,” following the incident.

“Iran preserves the right to take reciprocal measures and will decide the type of response and punishment against the aggressor,” Kanaani said, according to IRGC-affiliated Fars News.

The foreign ministers of Iran and Syria also accused Israel of authoring the attack, with Iranian Foreign Minister Hossein Amir-Abdollahian calling it a “violation of all international obligations and conventions” and demanding a “serious response” from the international community.

Syrian Foreign Minister Faisal Mekdad described the strike as a “gross violation of international regulations, especially the 1961 Vienna Convention on Diplomatic Relations,” according to a readout of his call with Amir-Abdollahian.

Zahedi, the slain commander, was previously the commander of IRGC’s ground forces, the commander of IRGC’s air force, and the deputy commander of the IRGC’s operations.

United States State Department spokesperson Matthew Miller said the US did not “have confirmation either of the target or the responsible party” at a briefing on Monday.

“Before we have gathered information about what exactly this was, I don’t want to speak to it specifically,” Miller added. “But of course, we’re always concerned about anything that would be escalatory or cause an increase in conflict in the region.”