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

Meanwhile, three soldiers were killed in an attack in Diyarbakir’s historic Sur district, which has been under a curfew since December as the security forces battle militants who are linked to the outlawed Kurdistan Workers’ Party, or PKK. The private Dogan news agency reported heavy fighting in Sur, where the military says at least 134 militants have been killed since December.

A statement from the local administrator’s office for Sur said the curfew — which bars residents from leaving homes and observers or journalists from entering to monitor the fighting — was enlarged to enable the security forces to ‘‘restore public order’’ in neighborhoods where the militants had allegedly dug trenches.

Associated Press