Thousands of people have fled a district of the mainly Kurdish city of Diyarbakir in southeastern Turkey after authorities fighting Kurdish militants there expanded a 24-hour curfew to include five more neighborhoods.

A statement from the local administrator's office for Diyarbakir's historic Sur district said the curfew — in place since December — was enlarged on Wednesday to enable the security forces to "restore public order" in neighborhoods where militants linked to the Kurdistan Workers' Party, or PKK, had allegedly dug trenches and set up barricades and explosive devices.

Turkey's military said three security force members were killed in an attack in Sur Wednesday, while the Dogan news agency reported heavy fighting.

An Associated Press journalist witnessed more than 2,000 people leaving Sur as the expanded curfew was announced.