The Tennessee National Guard named the two pilots who died in a Black Hawk helicopter crash in Madison County, Ala.,near the Tennessee state line,on Wednesday.

Daniel Wadham, 39, and Danny Randolph, 40, were killed during a training flight in which their helicopter "rapidly descended and impacted the ground," the Tennessee National Guard said in a statement Thursday. Both of them held the rank Chief Warrant Officer 3 and had served for 15 and 13 years, respectively.

They were approaching the Huntsville Executive Airport when the helicopter crashed near Alabama Highway 53 and Burwell Road, the Guard said. The cause of the crash is still under investigation.

"Words cannot express my sorrow for the loss of these two Tennessee National Guardsmen," said Brigadier Gen. Warner Ross, Tennessee's adjutant general.

No other service members or civilians were harmed, authorities say. They were the only people on board.

Tennessee Gov. Bill Lee said he and his wife are "saddened by the tragic loss of two Tennessee National Guard members. Please join us in lifting their families up in prayer & support during this time of unspeakable grief."

The Madison County Sheriff's office said debris could be scattered across the area near the crash site and asked that people don't touch or try to move it.