At least 31 people were killed when a ferry in southern Philippines caught fire Thursday.

The fire “raged overnight for eight hours,” impacting an estimated 250 people that included passengers and crew members who were onboard, The Associated Press reported.

A large number of the survivors in the incident had jumped ship and were then rescued by either the coast guard, navy and nearby ferry and fishermen, per the AP.

Search and rescue efforts for missing people onboard the MV Lady Mary Joy 3 continue and are somewhat challenging because the number of missing people isn’t exactly known at this point. The number of people onboard the ferry is also not completely clear as of yet.

What happened with the Philippines ferry fire?

The ferry was on its way from southern port city Zamboanga to Jolo Town when the fire started around midnight. The ferry was ultimately towed to the Basilan shoreline. Some residents on the shore witnessed the fire and jumped into action to try to help, CNN reported.

“Some of the passengers were roused from their sleep due to the commotion caused by the fire. Some jumped off the ship,” Gov. Jim Hataman of the southern island province of Basilan told the AP.

The cause of the fire has not been clear or disclosed at this time.

Some passengers were alerted by an explosion and jumped off the boat.

What other maritime incidents has the Philippines experienced?

According to BBC, the Philippines has experienced other maritime issues in the past. “Vessels are often overcrowded with many ageing ships still in use.”

Last year, a fire on a high-speed ferry killed at least seven people, BBC reported.

A ferry crashed into a fuel tanker in 1987 off Philippine shores, killing more than 4,300 people — making it “the world’s worst peacetime maritime disaster,” per the AP.