The latest Israeli strike on a Syrian air base in Homs province targeted Iranian officials, the Saudi-owned pan-Arab television station Al Arabiya reported Monday.
Nine people were reportedly killed in a strike on the T4 air base overnight Sunday, Syrian media said.
Damascus accused Israel of the strike on the base, known to be used by Iranian Revolutionary Guards in the war-torn country. Israel has not corroborated the reports.
An official with the Britain-based Syrian Observatory for Human Rights told Al Arabiya that the fatalities in the strike were "Iranian officials or fighters affiliated with the Syrian regime."
"This was most likely an Israeli strike," the official said.
Arab social media said the target was an IRGC gathering on the base. Some posts said a drone control unit and anti-aircraft defense systems were also destroyed in the strike.
Also on Monday, Israel threatened a "harsh response" to any attempt by Syrian forces advancing against southern rebel areas to deploy in a Golan Heights frontier zone that was demilitarized under a 44-year-old U.N. monitored truce between the neighboring foes.
Syrian government forces backed by Russia have launched an offensive in the southern Daraa province and are widely expected to move on rebel-held Quneitra, which is in a part of the Syrian Golan covered by the armistice.
Israel worries that Syria's President Bashar Assad could let its enemies Iran and Hezbollah move forces into the area, giving them a foothold near its border.
"For our part, we will observe the 1974 agreement, and there, too, we will insist that every last letter is upheld, and any violation with meet a harsh response from Israel," Defense Minister Avigdor Lieberman said Monday.
Commenting on the alleged strike in Syria, Lieberman said, "I read about it in the newspapers and I have nothing to add. Or perhaps just one thing – that our policy has not changed. We will not allow Iran's military entrenchment in Syria and we will not allow Syrian soil to be turned into a vanguard against the State of Israel. Nothing has changed. There is nothing new."