Islamic State militants have carried out offensives on multiple fronts in recent days, gaining territory and killing dozens of civilians in the central Syrian province of Hama, residents there said, and advancing on Wednesday into the chaotic Yarmouk district on the southern edge of Damascus.

The advances appeared to be intended, in part, to reassert the extremist group’s power, just days after its rival, the Nusra Front, along with a coalition of other insurgent groups, seized the northern city of Idlib, the second provincial capital to fall completely out of government control in Syria’s four-year conflict.

The leader of Nusra, a branch of Al Qaeda, posted an audio statement on social networks on Wednesday declaring that his group would not seek to monopolize power in Idlib. The leader, Abu Mohammad al-Jolani, called for a consultative council to rule the city with representatives from all factions of the rebellion against President Bashar al-Assad. He also called for the establishment of an Islamic law court “to solve the people’s problems.” […]