BAGHDAD — On Nov. 10, the Popular Mobilization Units (PMU) announced they blocked the road between Mosul and Raqqa, thus cutting the supply lines between the cities claimed by the Islamic State (IS) as its capitals. Days later, on Nov. 16, Hadi al-Amiri, a prominent PMU leader and the head of the Badr Organization, said that Syrian President Bashar al-Assad had called on the PMU to enter Syria after liberating the Iraqi territories.

Calls for the PMU to intervene in Syria are not new, as many PMU spokesmen had previously mentioned this possibility when the operations to liberate Mosul first started in October. Now, however, the Syrian regime itself — and its direct leadership in particular — has called on the PMU’s intervention, which means that the sectarian war in the Middle East is entering a new phase.

Syria has never made an official call like that before. For instance, Hezbollah’s intervention in Syria did not follow a call; the party believed the battle in Syria to be its own and took part either as a personal initiative or in response to an Iranian command.

In addition, Assad’s call was not addressed to the Iraqi president or prime minister, but rather directly to the PMU leadership, and such a call cannot be conceived through official channels because it would be rejected.