Eleven people were killed after being swept by tidal waves into the sea from the southern coast of Indonesia's East Java province on Sunday, said a local disaster management official.

The accident occurred at about 00:25 local time on Sunday when 23 people were conducting a traditional ritual at the Payangan beach in Jember district, head of the Disaster Management and Mitigation Agency Operation Unit in East Java, Budi Santosa said.

"Suddenly, tidal waves came and swept them into the sea. It was at the southern coast of Java island, and the waves are huge. They had been forbidden to do such activity," he told Xinhua by phone.

Twelve others survived the incident, he added.