At least five people have been killed and 41 remain missing after an Indonesian passenger ferry carrying 271 people caught fire at sea on Sunday (2), the country’s search and rescue agency said.

The vessel, the KMP Mutiara Sentosa 2, was sailing from Surabaya in East Java to Makassar in South Sulawesi when the blaze broke out between 6 a.m. and 7 a.m. local time off the northern tip of Madura Island.

The National Search and Rescue Agency, Basarnas, said 232 passengers and 39 crew were on board. By Sunday afternoon, nearby vessels had rescued 225 people and recovered five bodies.

A slow rescue in rough seas

The ferry operator, PT Atosim Lampung Pelayaran, alerted rescuers about an hour after the fire started, after the captain reported the vessel ablaze. Contact with the ferry was then lost.

Authorities later fixed its position roughly 19 nautical miles (35 km) north of Buruan Sapudi Island by establishing communication with a nearby cargo ship. That vessel could not approach the burning ferry because it was carrying flammable cargo.

Footage released by Basarnas showed thick black smoke pouring from the ship as passengers in life jackets gathered on deck. Videos circulating on social media appeared to show people crowded on the upper decks, some jumping into the sea as the flames spread. The ferry was later reported to be almost entirely engulfed, with a tugboat and a passing vessel moving in to take passengers off.

Conditions slowed the response. A rescue vessel dispatched from Surabaya was expected to take about six hours to reach the scene, and a rigid inflatable boat sent from a nearer rescue post turned back because of rough seas and high waves. The Indonesian navy deployed a warship to assist.

The cause of the fire was not immediately known.

A recurring toll

Indonesia is an archipelago of more than 17,000 islands where ferries are essential transport, and maritime accidents are frequent — a pattern attributed in part to weak enforcement of safety rules and to vessels operating beyond capacity.

The search for those still unaccounted for was continuing.