Israeli bombing of the Syrian capital Damascus overnight Thursday into Friday led to the killing of seven people, including four Iranian officers, a Syrian observatory center said. 

The London-based Syrian Observatory for Human Rights (SOHR) reported, quoting local sources, that the bombing killed three members of the Syrian regime, including two officers, and four Iranians. 

It added that Israeli missiles targeted the Damascus International Airport area.

The group also said the attacks took place after the arrival of a cargo plane to the targeted area, adding that it is unclear “whether the plane arrived from Iran or from another area inside Syrian territory."

Syrian official news agency SANA reported late on Thursday that the army's air defenses "intercepted hostile targets in the airspace of Damascus."

Citing a military source, SANA added that "at 23.45 p.m. [2145GMT] on Thursday, the army observed hostile missiles coming from over the occupied Syrian Golan Heights, and immediately the army air defenses intercepted and downed a number of them before they reach their targets."

"The hostile missiles came from over the occupied Syrian Golan," it added, referring to the Israeli warplanes. 

Israeli officials, however, have yet to officially claim responsibility for the reported strike.

Since the outbreak of the Syria conflict in early 2011, Israel has occasionally struck positions inside the war-torn country.

Iranian-backed forces and Lebanese Hezbollah militants have been fighting alongside Syrian regime forces since 2012.

Assad regime helicopter downed in northwest Syria

A Syrian opposition group reported Friday that they downed a Syrian regime helicopter in a "de-escalation zone" in northwest Syria.

The helicopter was hit directly while flying over the western Aleppo province, in a rural area of Aleppo that falls within the de-escalation zone of the neighboring province of Idlib.

The Syrian opposition aircraft observatory said that after taking off from Hamah Military Airport, a regime warplane returned to the runway as the traffic control tower issued a warning about the downed helicopter.

On Tuesday, three people were killed after a regime helicopter was hit by the opposition while flying over the village of Al-Naiyrab, west of the town of Saraqib, in eastern Idlib, also near the Aleppo province.

Flouting a cease-fire, the Assad regime and its allies have continued intensified air and land attacks on civilian settlements in the Idlib de-escalation zone.

The regime managed to take control of wide swathes of Idlib and is poised to seize control of the strategic M5 highway, which connects the capital Damascus to Aleppo, Syria's second-biggest city.

In September 2018, Turkey and Russia agreed to turn Idlib into a de-escalation zone in which acts of aggression are expressly prohibited.

But more than 1,800 civilians have been killed in attacks by regime and Russian forces since then, flouting both the 2018 cease-fire and a new one that started on Jan. 12.

More than 1.7 million Syrians have moved near the Turkish border due to intense attacks over the past year.

Turkey remains the country with the most refugees in the world, hosting more than 3.7 million migrants since the start of the Syrian civil war in 2011.