At least 15 people died when two boats sank in rough waters Indonesia, authorities said, and rescue workers scrambled to search for dozens believed missing.

Ferry accidents are common in Indonesia, a vast archipelago, especially during the Islamic holiday of Eid when millions make the annual journey by land, sea, and air to their hometowns after the holy fasting month of Ramadan.

A longboat carrying around 43 people sank off Makassar on Sulawesi island, leaving 13 dead, and a speedboat carrying 30 passengers sank off South Sumatra, killing at least two.

Authorities including the Indonesia search and rescue agency, police, and military deployed speed boats and dozens of personnel to search for survivors. “We still don’t have clarity on how many survived...as the search is still ongoing,” said Toto Mulyono of the Palembang search and rescue office in South Sumatra dealing with the speedboat.

Amiruddin of the national search and rescue agency in Makassar said 22 people had been rescued there.