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.

A heatwave with temperatures exceeding 40 degrees Celsius, or 104 Fahrenheit, on several days this month was expected to last through Monday.

MADRID - As Spain enters its third week of heatwave alerts, firefighters continue to battle blazes in the northwest and west of the country, with army units deployed to help contain the blazes.

Firefighters in Spain continued to battle major forest fires in at least 16 locations on Friday, as the country reels from one of its most devastating summers yet, according to the Interior Ministry.

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.

The fire was brought under control overnight, after a blaze in the Tres Cantos area killed one person and prompted evacuations, the authorities said.View on euronews

Fire crews in Greece, Spain, and Portugal are racing to contain wildfires. Calmer winds on Thursday have helped slow the blazes. Southern Europe remains at high risk due to hot, dry

The European Union has sent two planes to assist Spain in taking care of wildfires, after Spain activated the EU Civil Protection Mechanism for the first time ever for forest fires.

Three were arrested in a region where two volunteers died fighting the flames. Read more at straitstimes.com. Read more at straitstimes.com.

By Michael Francis Gore, Charlie Devereux and Ana Cantero VILLANUEVA DE LA SIERRA, Spain (Reuters) -Spain battled 14 major fires on Friday as authorities warned of "unfavourable conditions" to tackle flames that have already killed seven people and burned a surface area the same size as London.