"The immediate task is to bring all interests together who want to destroy Daesh, including Russia, including Iran, including our Muslim allies, to make that the major priority," Sanders said during Democratic presidential candidate debates on Sunday.
He added that Iran and Russia should also be involved in the political settlement of the Syrian crisis.
Since 2014, vast territories in Iraq and neighboring Syria have been occupied by Daesh militants, who have proclaimed a caliphate on the land under its control. The terrorist group is outlawed in many countries, including Russia and the United States.
The United States created an international coalition of some 60 countries, to participate in an aerial campaign against the Daesh targets in Syria and Iraq. However, in Syria, the coalition operates without the approval of Damascus or the UN Security Council.
On September 30, Russia began carrying out separate airstrikes against the terrorist group, at the request of Syrian President Bashar Assad.