New footage has emerged on X of what appears to be a possible explosion moments before the Douglas C-54 Skymaster cargo plane crashed into the Tanana River near Fairbanks, Alaska, on Tuesday evening. 

AP News said the Douglas C-54, a variant of the DC-4 airliner, crashed about 7 miles from Fairbanks International Airport. 

Clint Johnson, chief of the National Transportation Safety Board's Alaska regional office, said the cause of the C-54's crash remained unknown, and an investigation is being launched.  

Pilot Michaela Matherne, who was en route from the village of Galena to Fairbanks at the time of the incident, recounted, "When we were in the air there was speculation that it was a cabin that caught fire." 

X user Rawsalerts posted land-based security footage of what appears to show a catastrophic failure that brought down the World War II-era cargo plane.

We don't want to speculate too much about that failure because an NTSB investigation has yet to be completed, but the video above appears to show an explosion, possibly occurring in one of the engines. 

Here's what X users are saying:

Next question: What caused the explosion?