IAF responds to Monday's rockets against northern Israel by striking targets in Quneitra; Syrian NGO says 12 were killed.

The Israeli Air Force (IAF) bombed several terror targets in the city of Quneitra, Syria overnight Tuesday, following a volley of rockets on the Golan Heights, Syrian media reported.

Between four and twelve people were killed in the airstrike; exact numbers have varied among news outlets.

"Israeli planes flying over the occupied Golan Heights launched rockets into southern Syria's Quneitra province at around 1:15 am (2215 GMT). Rockets hit Base 90 -- a Syrian military airbase -- and regime bastion Baath City. Four people were killed," the Syrian Observatory for Human Rights, a Non-Governmental Organization (NGO), reported.

The Syria-Parash news outlet and Walla! listed twelve people killed, adding that several terror targets struck belong to the regime of Syrian President Bashar Assad.

The Municipality of Quneitra and several Syrian army outposts were also struck in the attack.

"A second strike on another area of Baath City also caused casualties, but we have been unable to confirm the number so far," Observatory director Rami Abdel Rahman told AFP. Base 90 was also hit, he added.

The IDF Spokesperson's office has declined comment.

On Tuesday, two rockets fired from Syria into the Golan Heights exploded in open areas in the Golan Regional Council. No injuries or damage were reported. Military experts told Walla! News Tuesday that the rocket fire was likely the work of pro-Palestinian groups expressing solidarity with Hamas, as Israel entered the eighth day of its self-defense effort, Operation Protective Edge.

Additional mortars were fired into Israel on Sunday; the IDF returned fire.