"Israeli occupation jets launch air strikes targeting the surroundings of Daraa city," said Damascus's official news agency SANA, without immediately providing further details.

The Syrian Observatory for Human Rights monitor said Israel targeted a military site once belonging to ousted president Bashar al-Assad's army but now used by the forces of Syria's new authorities.

The Britain-based Observatory reported that a fire broke out, with ambulances rushing to the scene amid reports of casualties.

Since Assad's overthrow in December, Israel has carried out hundreds of air strikes in Syria and deployed troops to a UN-patrolled buffer zone on the strategic Golan Heights.

Israeli Defence Minister Israel Katz said the air force conducted a strike on Damascus on Thursday, with the military saying it had hit a "command centre" of the Palestinian Islamic Jihad group.

The Observatory reported one fatality in that strike, with SANA saying it targeted a building in the capital.

The Israeli military said the "command centre was used to plan and direct terrorist activities by the Palestinian Islamic Jihad" against Israel.

A source in Islamic Jihad said a building belonging to the group had been hit by Israeli jets, adding there were "martyrs and wounded" in the strike.

Ismail Sindawi, Islamic Jihad's representative in Syria, told AFP the targeted building had been "closed for five years and nobody from the movement frequented it". Israel was just sending a message, Sindawi said.

Even before Assad's fall, during the Syrian civil war that broke out in 2011, Israel carried out hundreds of strikes in the country, mainly on government forces and Iranian-linked targets.