Saudi Arabia's foreign minister on Tuesday poured cold water on Russian calls to join forces with the Syrian authorities against "Islamic State" (ISIS) terrorists, insisting it was impossible to work with President Bashar al-Assad, AFP reports.

Moscow, one of Assad's few remaining allies, has called for coordination between the Syrian government and members of an international coalition fighting the extremist group, which controls swathes of territory in Syria and Iraq. But Saudi Foreign Minister Adel al-Jubeir insisted there would be no cooperation with the Syrian regime after meeting Russian counterpart Sergei Lavrov in Moscow.