A cargo plane with eight people on board crashed late Saturday near the northern Greek city of Kavala, according to media reports.
State television ERT reported that the plane was an Antonov An-12 owned by a Ukrainian company that was en route from Serbia to Jordan.
The pilot had requested an emergency landing due to an engine problem, and contact was lost shortly afterwards.
Video footage uploaded to ertnews.gr shows the plane on fire and rapidly descending before hitting the ground, followed by what appears to be an explosion.
Firefighters could not confirm the type of aircraft, but said initial reports indicated there were eight people on board.
A statement said it deployed 15 firefighters and seven fire engines to help put out the fire that broke out after the crash.
More rescue workers are on their way.
Special forces in protective suits
Residents near the cargo plane crash site have been asked to keep their windows closed.
Journalists and spectators were also asked to leave the area.
The Greek state broadcaster ERT showed pictures of the burning crash site on Sunday night.
The firefighters had withdrawn, special forces in protective suits moved in.
Two firefighters were taken to the hospital with respiratory problems, one of the helpers told journalists.
It is suspected that the machine had toxic material on board.
At first there was talk of ammunition.