By Michael Francis Gore, Charlie Devereux and Ana CanteroVILLANUEVA DE LA SIERRA, Spain (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.

Spain was fighting 14 major fires, according to Virginia Barcones, general director of emergency services. Temperatures were expected to climb over the weekend.

Firefighters in Spain, Portugal and Greece battled ongoing wildfires Friday, an important religious holiday in all three countries, as persistent hot, dry conditions challenged efforts to contain the blazes.