All eight crew members were killed when a Ukrainian-operated cargo plane crashed in Greece en route from Serbia to Bangladesh carrying military goods, the Serbian defence minister said Sunday.

All eight bodies were found and are being recovered. During a briefing by the Greek Fire Brigade earlier in the afternoon, its spokesman, Ioannis Artopoios stressed that experts at the crash site haven't found any 'dangerous materials'. 

"Sadly, according to the information we have received, the eight members of the crew died in the crash," Serbian Defence Minister Nebojsa Stefanovic told a news conference.

The Antonov An-12 took off from Nis airport in southern Serbia at 8:40 pm (1840 GMT) on Saturday, carrying "around 11 tonnes of military industry goods" namely mines from Valir, a private Serbian company, to the Bangladeshi defence ministry, Stefanovic said.

Ukraine's foreign ministry said the eight flight crew were Ukrainian citizens. "The preliminary cause of the accident is the failure of one of the engines," said spokesman Oleg Nikolenko on Facebook.

Denys Bogdanovych, general director of Meridian, the Ukrainian airline operating the plane, also told German broadcaster Deutsche Welle that the crew were all Ukrainian.

Witnesses said they saw the privately operated Antonov on fire and heard explosions. Videos shared on social media showed the plane engulfed by a giant fireball as it hit the ground late Saturday.

Debris was scattered across a wide area and the crash site, surrounded by fields, was visible from the air, an AFP photographer said.

"We heard a deafening noise (and saw) a fireball approaching the ground. Then came the explosion," Sofia, a mother of three from the nearby village of Antifilipi told Athens News Agency (ANA).

The Greek fire brigade said the plane crashed at around 11:00 pm (2000 GMT) near Paleochori village around 23 kilometres (14 miles) northwest of the city of Kavala in northern Greece.

Greek air traffic control said the plane had requested clearance for an emergency landing at the airport in Kavala but did not make it.

The Bangladesh military confirmed that they had been the intended recipients of the cargo.

The aircraft had been carrying "training mortar shells procured from Serbia for the Bangladesh Army" and border guard, said the military's public relations office.

"There was no weapon in the shipment and the shipment was covered by insurance," it added.

Biological and chemical weapons experts from the Greek army combed the crash site on Sunday, giving the "all clear" to rescue teams, said fire service spokesman Artopoios. The service then opened safe passages for the rescuers to recover the bodies, he added.

Two firemen were taken to the hospital early on Sunday with breathing difficulties because of toxic fumes.Villagers were forbidden from going into the nearby fields until authorities could remove the wreckage and unexploded munition.

People living within a two-kilometre radius of the crash site were asked to stay inside and wear face masks late Saturday.