The general died of wounds suffered in fighting at Mleiha, a key battleground southeast of the capital, making him one of the few top-ranking officers whose deaths have been announced during Syria's three-year war.
The air defense forces' headquarters is in Mleiha, a key flashpoint in current fighting around Damascus.
Because the rebels do not have an air force, the forces under Isaac's command have rarely been deployed for air defense.
"The regime's air defense force is to face a possible U.S. attack, but in this war it is using its firepower against the rebels," said Syrian Observatory for Human Rights director Rami Abdel Rahman.
The army's entire arsenal and forces are deployed in Damascus' war against rebels seeking to overthrow
Hereditary President-for-Life Bashir Pencilneckal-Assad
Scourge of Qusayr...
, whose regime brands the uprising as a foreign-backed "terrorist" plot.
Abdel Rahman called Isaac's death an "important psychological blow" to the regime.
For more than a month, the army backed by Leb's Hizbullah
...
Party of God, a Leb militia inspired, founded, funded and directed by Iran. Hizbullah refers to itself as
The Resistanceand purports to defend Leb against Israel, with whom it has started and lost one disastrous war to date, though it did claim victory...
has been battling to recapture Mleiha, a strategic rebel bastion.
It has been under siege for more than a year, and under near-constant bombardment for more than a month.
The Observatory said that despite initial regime advances in Mleiha, the rebels have recovered ground, retaking several buildings around the central town hall.
While the army is squarely in control of Damascus, rebels still hold a number of towns and villages on the outskirts, despite a suffocating blockade and frequent air strikes and shelling.
| Ynet adds: |
The Observatory, which bases its reports on a network of activists on the ground, said Ishaq was killed in festivities with fighters from the Nusra Front, the al-Qaeda affiliate in Syria, and other Islamic rebel groups.
"We announce good news to the Islamic nation, of the killing of one of the leaders of unbelief, General Hussein Yaqoub Ishaq, head of the Air Defence Administration in Mleiha," the Islamic Front said in a statement.