“Yes, we are women,” said Umm Saif, a nickname meaning “mother of Saif,” giggling from behind her black face cover. “But don’t be mistaken. We can fight, too. We will all fight.”

Here in the Shiite heartland of Iraq, volunteers have revived battalions of the Mahdi Army, one of the dominant groups preparing for battle following the call for a “defensive jihad” June 13 by Grand Ayatollah Ali al-Sistani, one of the highest authorities in the Shiite faith…

All factions in the city have started mobilizing, preparing, as they call it, “for war.” But, almost everybody here says, the war is against the “terrorists” — the jihadists of the Islamic State in Iraq and Syria who have seized broad stretches of northern territory — and not against Sunnis.

This reluctance to lump together the Sunnis of ISIS with the Sunnis of Iraq could suggest that some Shiites, the majority sect in the country, are heeding the call of Ayatollah Sistani and other clerics to embrace a national identity instead of a religious one, despite months of fierce sectarian battles across Iraq that preceded the ISIS invasion two weeks ago. Several ayatollahs have issued fatwas against anyone feeding the fire of sectarianism.