Douglas DC-4 plane with two passengers crashes into Alaska river

First responders conducted an 'active rescue' on Tuesday morning after a plane plummeted into the Tanana River area of Fairbanks, Alaska.

Alaska State Troopers joined together with local, state and federal agencies to respond to the crash, which took place near Kallenberg Road, officials reported.

There were two people were on board the Douglas DC-4 aircraft, according to the Federal Aviation Administration. The condition of the passengers on board remains unknown. 

Alaska State Troopers reported that the Douglas C-54 Skymaster airplane had crashed into the Tanana River near Fairbanks - The C-54 is a military version of the Douglas DC-4, which was a World War II-era airplane.

A witness reported hearing a massive explosion just before 10 am local time - and saw a plane flying overhead with an engine on fire.

The witness said he heard what sounded like another explosion as well as a crash, and then saw a huge cloud of dark smoke. 

First responders conducted an 'active rescue' on Tuesday morning after a plane plummeted into the Tanana River area of Fairbanks, Alaska

The number of passengers on board the Douglas DC-4 aircraft is currently unknown

A witness said he heard what sounded like another explosion as well as a crash, and then saw a huge cloud of dark smoke

'Please avoid the area and expect an increased first responder presence in the area,' troopers said.

'We acknowledge the ongoing situation involving the Douglas DC-4 aircraft on the Tanana River near Kallenberg Road,' the airport said in a statement provided by spokesman Zak Mitchell. 'Alaska State Troopers are actively leading the response and we are cooperating with them.' 

This is a developing story, check back for updates.