The aircraft was completely destroyed while a second F-16 was heavily damaged from the explosion.
Two people were wounded and treated at the scene.
Injuries sustained were mainly related to hearing damage from the huge explosive noise.
The F-16 military aircraft caught fire near a hangar during routine ground maintenance.
Some reports have claimed the jet ignited during a technical manoeuvre.
Several explosions followed with plumes of thick black smoke filling the sky for miles around.
Firefighters are being helped by civilian firefighters to tackle the blaze at the airbase.
Around 30 men are involved in the operation, while several ambulances also arrived at the scene.
The military airfield is two miles southeast of Florennes, a Walloon municipality of southern Belgium.
It is home to the 2nd Tactical Wing, operating F-16 Fighter Falcons.
Until July 2009, the airbase was also home to the Tactical Leadership Programme, a joint training programme established by 10 NATO members.
This is a breaking story. More to follow.