ISTANBUL — The Turkish military said Thursday that it had accidently killed at least 35 Turkish cigarette smugglers in airstrikes after mistaking them for separatist fighters in the Kurdish border region with Iraq, infuriating many of Turkey’s long-oppressed Kurds. Most of the dead were between 17 and 20 years old.

Political opponents denounced the prime minister, and angry crowds gathered in central Istanbul, hurling stones at shop windows and striking passing cars with bars. The police used tear gas and water cannons to disperse them, Turkish news agencies reported. In several predominantly Kurdish cities in the southeast, security forces also used tear gas, according to local news reports.