"Army air defences repels an Israeli air aggression that targeted a number of industrial sites in Sheikh Najjar industrial zone, north-east of Aleppo, and downed a number of the hostile missiles," the official SANA news agency said, citing an unnamed military source.

A number of residents of Aleppo city told AFP that the attack led to a power cut in the whole city.

The Syrian Observatory for Human Rights said the Israeli bombardment hit "ammunition stores belonging to Iranian forces and allied groups, and caused huge explosions."

If confirmed, this would be the first attack on Syrian territory since US President Donald Trump signed Monday a proclamation recognising Israel's 1981 annexation of the strategic Golan Heights plateau which it seized from Syria in the 1967 Six-Day War.

Earlier this year in January, Israel targeted a number of Iranian installations in the country, hours after intercepting a rocket fired from Syrian territory.

The Syrian Observatory for Human Rights said 21 people, mostly Iranians, were killed in those attacks.

Israel insists that it has the right to continue to target positions in Syria held by Iran and its Lebanese ally Hezbollah.

In May 2018, Israeli strikes killed 27 pro-regime fighters including 11 Iranians in strikes on dozens of Iranian targets inside Syria.