In what is the largest civilian death count in Turkey’s history fighting Kurdish rebels, 35 civilians have been killed in an air strike at an Iraq border point. U.S. drones, which had been relocated from Iraq, had detected the group earlier and mistook them for rebels.

Although many of the victims may have been diesel smugglers, they were not working for the Kurdistan Workers Party (P.K.K.) rebels. Over a dozen of those killed were reportedly teenagers, and some were the sons of village guards. Most of the survivors were said to be wounded, but only one injury was officially reported. Witness put the number of injured at fifteen.

Kurdish officials in Turkey claimed they had warned the military of the smuggler’s presence but were ignored. Meanwhile, protests in Istanbul condemning the air strike were met with water cannons and tear gas. No injuries were reported, but several people were arrested.

In recent days, Iraqi Kurdish officials had complained Turkey was still conducting air strikes, as they have since summer. Then as every summer, the Turkish military stepped up attacks against rebels who use remote northern Iraq for its hideouts. This year’s attacks, however, were more intense.