The New York State Division of Military and Naval Affairs says that the crash happened in Mendon around 6:30 p.m.

"According to the 911 reports ... there were calls of a sputtering, the sounds of an engine and that the aircraft was flying very low, more low than normal," Monroe County Sheriff Todd K. Baxter said in a news conference.

When first responders arrived they found a helicopter in flames. 

"They went into life-saving mode, trying to rescue anybody that could be on the aircraft or in the area," Baxter said.

The UH-60 Black Hawk medical evacuation helicopter was carrying three New York National Guard soldiers at the time. 

"This is a heavy, heavy burden upon all of us. These are our freedom providers... We lost three brave Americans today in the service of our country," Baxter said.

The cause of the crash remains under investigation by local and federal agencies.