Islamic State “has lots of experience in warfare, but we don’t have experience in urban warfare so we are trying to fill this gap,” Manda said. “Our experience is in guerrilla warfare because in the ’90s we fought Saddam [Hussein’s Iraqi army] forces through guerrilla warfare in the mountains. Our experience in urban warfare is lacking.”…

A peshmerga officer, who did not want to be identified because he was not authorized to speak publicly, said top commanders shared the responsibility for the force’s initial defeats. For months, they assumed Islamic State was only girding for a battle between Sunnis and Shiites among the historically volatile Iraqi Arab population.

“They said ISIS won’t come here, they won’t come after the Kurds,” he said, using an acronym for Islamic State. “They said they will only come after [former Prime Minister Nouri] Maliki and presumed they would only attack Mosul and Baghdad.”

The peshmerga did not train for street battles until 2010, Brig. Gen. Salih said. And even then, only a small percentage of the forces received the training.