Nearly a month after American troops officially withdrew from urban areas in Iraq, they are quietly going back in again, patrolling the streets of towns and cities where, despite improvements in security, violence remains an everyday occurrence, reported BBC.
By the US military's own reckoning, Mosul and its surrounding region is the most dangerous area in Iraq.
On average they calculate there are four attacks here every day - explosions, shootings, suicide bombings. That is down from six per day in January - progress, of sorts.
Since 30 June, Iraqi forces have been entirely responsible for maintaining security in urban areas. But the Americans want to keep a close eye. So they are maintaining a limited number of joint patrols inside cities like Mosul.
Lt Joel Brown was going into Mosul for the first time since the handover. When he and his platoon were last in the city, they came under attack - a grenade was thrown at their convoy from one of the many narrow alleyways along their route.
"The grenade thrower was right behind that red car," Lt Brown said, pointing out of the window of his armoured Humvee. "It bounced off the Humvee and blew up on the ground."
On the roof of the vehicle, a gunner swept the road from right to left, watching for similar threats. Many of the buildings on the way into town had either been reduced to rubble or were pockmarked by bullets. Six years after the US-led invasion, Mosul still looks like a city at war.