The killing of a terrorist leader of a Syrian armed group in an air raid last week does not serve the peace process in the war-ravaged country.

The killing of a terrorist leader of a Syrian armed group in an air raid last week does not serve the peace process in the war-ravaged country, Saudi Foreign Minister Adel al-Jubeir said Tuesday.

Zahran Alloush, the head of the Saudi-backed-and-financed Jaish al-Islam, a terrorist group operating in Damascus province, was killed on Friday in a strike claimed by the Syrian army.

"I don't know what the Russians have in mind," Jubeir told reporters, in reference to the killing.

The minister was speaking at a joint news conference in Riyadh with his Turkish counterpart Mevlut Cavusoglu.

Jaish al-Islam has fought off the Syrian army forces in its Eastern Ghouta bastion, east of Damascus.

Saudi Arabia is a key backer of armed takfiri groups battling the Syrian national forces, and Jubeir reiterated previous demands that President Bashar al-Assad be removed from power.

Moscow had accused Turkish President Recep Tayyip Erdogan and his family of involvement in the illegal oil trade with extremists of the so-called 'Islamic State of Iraq and the Levant' (ISIL) takfiri groups, claims Ankara has strongly denied despite video footages that prove the Russian accusations.