ISTANBUL (AP) — Rescue workers in Turkey were searching for people trapped under the rubble of a building that collapsed Tuesday in eastern Turkey.

The governor of Malatya province, Aydin Barus, said 15 people were thought to be in the two-story building at the time of the collapse but he could not give an exact number for those who remained trapped. He said rescue workers had heard from one person under the rubble and were trying to reach him or her.

Thirteen other people were rescued earlier and two were being treated in intensive care but were not in critical condition, authorities said.

A survivor told the official Anadolu news agency that a wall collapsed on him but he managed to get out with two friends. Semseddin Bozdemir said there were 15 to 20 people in the building when he entered.

The cause of the collapse was being investigated. Turkey’s emergency agencies dispatched over 260 personnel to the site.