All 48 people aboard an Antonov An-24 passenger plane that crashed in Russia’s Far East on Thursday were killed, regional authorities said, while police investigators announced they had launched a criminal probe into possible violations of air safety rules.

The Angara Airlines flight lost contact with ground dispatchers around 1 p.m. local time while flying several kilometers from the airport in the town of Tynda. The plane had originated in Khabarovsk, made a stop in Blagoveshchensk and was en route to Tynda. Among those on board were six crew members.

Emergency officials said the aircraft did not issue a distress signal or report any technical issues before it disappeared from radar. Rescue teams later located the charred wreckage approximately 16 kilometers (10 miles) from Tynda, a town of less than 30,000 people.

“According to preliminary reports, there are no survivors of the An-24 plane crash in the Tynda district. Rescue teams have reached the crash site,” Amur region Governor Vasily Orlov wrote in a message on Telegram, declaring a three-day period of mourning over the air disaster.

“This terrible tragedy has claimed the lives of 48 people,” Orlov wrote. “Once again, I extend my deepest condolences to the families and loved ones of the victims. The entire region grieves with you.”

Authorities initially reported that 49 people were aboard the plane.