Spain's defence ministry has said that a Greek F-16 fighter jet crashed into a hangar at a military base in Spain where it was participating in NATO training.
The defence ministry said on Monday that ten people died in the crash and 13 were injured.
The F-16 plane crashed shortly after taking off at the training centre in Albacete, 262 kilometres southeast of the Spanish capital of Madrid, according to the ministry statement.
"The plane, part of the Tactical Leadership Programme of NATO was carrying out a [training] exercise when during the take-off the plane lost power, crashing into the parking area for planes, crashing into various planes that were parked there," said the ministry.
"Seven of the injured are in a very serious condition," a defence ministry official told the AFP news agency.
Emergency crews are working to put the blaze out and determine how much damage was done to other planes involved in the NATO exercise, the ministry said.
National television footage showed flaming wreckage and a plume of black smoke where the plane crashed at the Los Llanos base.
The AP news agency said that most of the victims were not believed to be Spaniards, according to a defence ministry official, who spoke on condition of anonymity because ministry rules preventing him from being named.
A NATO spokeswoman declined to disclose details, referring questions to Spanish and Greek military officials, AP said.