A private jet carrying four people that was due to land in Germany but which continued to fly across Europe as air traffic controllers tried unsuccessfully to make contact crashed off the Latvian coast, authorities said. The jet “was flying between Spain and Cologne but when it changed course, air traffic controllers were not able to make contact”, the Latvian civil aviation agency said in a statement. The German newspaper Bild said that the plane had reported shortly after takeoff that there was a problem with pressurisation in the cabin. Fighter jets from Germany, Denmark and Sweden were scrambled to try to make contact with the crew in the air as the plane continued to fly across northern Europe, “but they saw no one”, Swedish search and rescue operation leader Lars Antonsson told AFP. The plane, an Austrian-registered Cessna 551, flew over Swedish airspace in the Baltic Sea before crashing into the sea off Ventspils just before 8pm (1800 GMT). The plane flew relatively steadily until it neared the Latvian coast, when it rapidly lost altitude. It crashed “when it ran out of fuel”, Antonsson said. The nationalities of the four onboard were not immediately known. German media said the passengers were a family of three – a man, a woman and their daughter – in addition to the pilot. “Rescue teams with boats and helicopters from Latvia, Lithuania and Sweden are working at the crash site,” the Latvian aviation agency said. “No human remains have been found,” Antonsson added. It is not known what caused the plane to fly off course. “We have no explanation at all, we can only speculate” about what happened, Antonsson said, “but they were clearly incapacitated onboard”. Agence France-Presse and Associated Press contributed to this report.