A top Russian general has been killed by an ISIS mortar strike in Syria as he tried to help Bashar al-Assad troops fight in the war-torn country.

Lieutenant-General Valery Asapov was in the Middle East and was 'at a command post of Syrian troops', according to the Russia's Defence Ministry.

He moved to Syria to assist commanders in the operation for the liberation of the city of Deir ez-Zor.

But he was 'mortally wounded' after a mortar strike was carried out by ISIS on Sunday.

Lieutenant-General Valery Asapov (pictured) has been killed by an ISIS mortar strike in Syria

Asapov was one of the senior Russian military advisers who travelled to Syria to help and he is one of the people who has been killed in the attack.

The Russian ministry said that Lt. Gen. Valery Asapov 'was at a command post of Syrian troops, assisting the Syrian commanders in the operation for the liberation of the city of Deir ez-Zor.'

State news agency Tass reported that 'as a result of a mortar shelling by the IS (Islamic State group), Asapov was mortally wounded.'

It comes as airstrikes targeted rural Aleppo in northern Syria on Sunday for the first time in months since a cease-fire took hold in the province.

Burning vehicles are seen under the debris of Al-Rahme hospital after an air strike was carried out in Han Seyhun town of Idlib, Syria on September 19, 2017

The Central Military Media, affiliated with the Syrian government, reported that Iranian drones successfully struck vehicles of the Islamic State group along the Syria-Iraq border in the south.

Meanwhile, Syrian media reported that government and allied troops have seized Maadan, a town north of Deir el-Zor and south of Raqqa, which has been scene to intense fighting with Islamic State militants.