Patients sit in a yard of Undata Regional Hospital in Palu, Indonesia's Central Sulawesi province. Picture: BNPB HANDOUT/Xinhua

Jakarta  - Hundreds of inmates escaped from a prison in the Indonesian city of Palu after a powerful earthquake caused its walls to collapse, local media reported on Saturday. 

There were 560 inmates in the prison and more than half of them escaped after Friday's quake, which was followed by a tsunami, chief warder Adhi Yan Ricoh said, according the state Antara news agency.  

He said guards could not stop the prisoners from escaping because the electricity was out and they were outnumbered.

A mosque is seen heavily damaged by earthquake and tsunami in Palu, Central Sulawesi, Indonesia. The powerful earthquake rocked the Indonesian island of Sulawesi on Friday, triggering a 3-meter-tall tsunami that an official said swept away houses in at least two cities. Picture: Rifki/AP

"Besides, the guards were also busy saving themselves," Adhi was quoted as saying. 

The authorities have not tried to recapture the fugitives because they were busy helping victims of the earthquake and the tsunami, Adhi said.