A 650-foot ferry was ablaze in the Baltic Sea on Saturday after an explosion on the upper deck, and firefighting ships were spraying the vessel with water to keep it from breaking apart and spilling some 170 tons of fuel, officials said.
There were 249 people aboard who were rescued by six ships that moved in to help after the explosion on the Lisco Gloria around midnight. Three were taken to hospitals by helicopter and another 26 were slightly injured, police said.
German officials and the ferry operator said the blast was not a terror attack, but appeared to have been a technical mishap.
"A terrorist attack can be excluded," said Wolfgang Harlos, a spokesman for Germany's Central Command for Maritime Emergencies in Cuxhaven.
Schleswig-Holstein state police spokesman Stefan Jung added, "the investigation is ongoing, but all indications so far suggest that the cause was a technical problem."
TV footage showed a fire on the top deck, while the decks below appeared to be gutted by the fire.
"People were lucky because it all happened on a major shipping route, that's why the other vessels were quickly on hand to rescue people," said Ulrike Windhoevel, a spokeswoman for Germany's maritime emergencies center.
Authorities allowed the blaze aboard the ship to burn because "there's a possibility it could capsize if we continue," a Danish navy duty commander said. No oil had spilled, he said.
"At the moment there are four ships at the scene, with more on their way. Their primary purpose is an environmental protection service. If there is an oil spill we can cordon off the scene," said the duty commander, who declined to be named in line with Danish military policy.
Windhoevel said firefighters were still spraying water on the ship's exterior to cool it down.
"But the firefighters cannot put out the blaze on the ship, because at some point it would sink because of all the water in it," she said.
Once the fire has stopped burning, authorities hope to be able to pull the ferry to a nearby harbor, where the accident's cause can be thoroughly investigated, Harlos said.
The Lithuanian-flagged ferry was traveling from the German port of Kiel to Klaipeda, Lithuania, authorities said.
Passengers and crew were evacuated by lifeboat and taken by another ferry to a naval base near Kiel, officials and the shipping company DFDS said. The passengers were mostly Lithuanians, DFDS spokesman Gert Jakobsen said.
Most of the passengers were taken to hotels for the night, but some drove themselves home, Windhoevel said.
Authorities said a four-person team was lowered to the ferry by helicopter and managed to anchor the vessel off the southern tip of the Danish island Langeland to keep it from drifting farther ashore.
Associated Press Writer Keith Moore in Stockholm contributed to this report.