VILLANUEVA DE LA SIERRA, Spain, Aug 15 (Reuters) - Spain battled 14 major fires driven by high winds and aggravated by heat on Friday as authorities warned of "unfavourable conditions" to tackle flames that have already killed seven people and burned an area the size of London.

The fires in Spain this year have burned 158,000 hectares or 610 square miles, according to the European Union’s European Forest Fire Information System. That is an area roughly as big as metropolitan London.

Spain is battling a series of devastating wildfires that have killed two people and destroyed thousands of hectares of forest and scrubland. There are currently 14 major active fires, Minister for Ecological Transition Sara Aagesen told radio station Cadena Ser on Wednesday.