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DAMASCUS, Oct. 11 (Xinhua) -- Dozens of militants with the Islamic State (IS) group were killed Tuesday by a Syrian air strike in the northern province of Aleppo, Syria's national TV reported.

The air strike targeted the IS militants in a cave in the vicinity of the Air Force Faculty, north to the town of Deir Hafer in the eastern countryside of Aleppo, said the report.

It added that Saudi IS commanders were among those killed in the cave strike.

Meanwhile, the report said the Syrian army continued to advance on Tuesday against rebel-held areas in the eastern side of Aleppo city, capturing the Jandoul Roundabout, which overlooks several rebel-held areas in eastern Aleppo.

The victory is the latest in a series of successful military offensives in Aleppo, where the Syrian army, backed by Russian air force, has recently captured key sections in rebel-held areas, in what activists called the first military advance against the rebel in eastern Aleppo in three years.

On the opposition side, the Syrian Observatory for Human Rights monitor group said at least 12 people were killed by Russian air strikes against rebel-held areas in Aleppo on Tuesday, saying the air strikes were the heaviest in days.

The escalation on Tuesday comes a day after the Syrian Foreign Ministry resent another invitation to the Syrians in rebel-held areas to leave, promising them secure passages into government-controlled areas, and safe accommodation.

The invitation is the latest in a series of calls by the Syrian government to the civilians to leave the rebel-held areas, and to the rebels to lay down their weapons.

On Sept. 22, the Syrian army declared a new offensive aiming to dislodge the rebels from the eastern part of Aleppo city, triggering a series of accusations from Western countries, who charged Russia and the Syrian army of committing war crimes in Aleppo.

On Tuesday, the head of the Observatory, Rami Abdul-Rahman, said that people in eastern Aleppo lost trust in Syrian authorities, as they fear to face imprisonment and integration.

Instead of having the civilians leave eastern Aleppo, he said that government should end siege to let relief aid in.

Aleppo, located near the borders with Turkey, is Syria's largest city and once an economic hub. It has been a focal point of clashes between the Syrian army and the rebels.

The rebels laid siege to western Aleppo districts after cutting the international road to Aleppo in 2014, a siege broken later by the Syrian army with the help of Hezbollah.