A helicopter plummeted into a rural stretch of Minnesota and exploded into flames Saturday afternoon, killing everyone on board, officials said.

The Robinson R66 went down around 2.45 pm in Lakeville, just west of Airlake Airport, roughly eight minutes after taking off from Sky Park Airport in Lydia, according to Lakeville Police and online flight data.

“The preliminary information we have is that the helicopter crashed under unknown circumstances and a post-crash fire ensued,” the National Transportation Safety Board (NTSB) said in a statement.

Authorities confirmed no survivors were found, but have not said how many people were on board. The single-engine turbine chopper, designed to carry a pilot and up to four passengers, had reached an altitude of 2,000 feet before suddenly plunging into a remote area near Highway Avenue and 219th Street West, about 25 miles south of Minneapolis.

Police said no one on the ground was hurt.

The victims’ identities have not yet been released. An NTSB investigator is expected to arrive at the crash siteon  Sunday, with both the NTSB and Federal Aviation Administration leading the investigation.