"I am not aware of any aircraft (working for us) that has crashed", Vítor Vaz Pinto told reporters in Avelar, Portugal.

He said there might have been some other event that misled people and spoke of the possibility of a “hot-dog stand” blowing up and that teams had been sent to the scene.

"There was an abandoned hot-dog caravan with bottles of gas, and this might have exploded, he said.

A source from the National Civil Protection Authority had said earlier that a firefighting Canadair combatting the flames in Pedrógão Grande, had crashed this afternoon.

A reporter for a Portuguese public broadcaster also said he heard a loud explosion in hills about 10 kiolmetres from the region where firefighters are battling the blaze.

Antena 1 public radio reporter Pedro Sa Guerra says there was thick smoke over the area on Tuesday caused by the devastating wildfire in Pedrogao Grande.

He says a local woman told him she saw a plane crash in a fireball.