Earlier, the pilot had reported engine trouble and was given permission for an emergency landing at Kavala but the aircraft's signal was lost soon after the call at 1942 GMT.

Images from the scene showed smouldering debris from the aircraft, operated by Ukraine's Meridian cargo airline, strewn in fields.

The Greek foreign ministry has lodged a demarche with Ukraine's ambassador in Athens over the need for Greece's prior notice by Ukraine regarding the nature of the aircraft's cargo, a Greek diplomatic source said.

Greek diplomatic sources said earlier on Monday that Greece would also protest to Serbia for the same reason.

Serbia’s foreign ministry was not immediately available for comment.

Serbia's defence minister Nebojsa Stefanovic said on Sunday morning the plane's cargo was made by Serbia's defence industry. It had taken off at 1840 GMT on Saturday from Nis in Serbia and the buyer of the cargo was the defence ministry of Bangladesh.

Greek authorities cordoned off the site on Saturday and later banned people from moving around and advised residents to keep doors and windows shut, as firefighters with the special disaster response unit were investigating the area.

A fire brigade official said on Sunday morning that white dust was floating in the air. In the evening, Greek authorities said that tests showed the substances released in the air after the accident were not toxic or hazardous to public health.

Greek opposition parties have accused the conservative government of not providing information on the cargo and urged it to investigate the incident further.

A prosecutor has launched an investigation into the accident. The bodies of the crew members will be examined by a coroner, according to state TV ERT.