The head of Russia's Federal Security Service blamed Al-Qaeda Wednesday for a recent series of deadly forest fires in Europe, saying they were set by arsonists as part of the group's strategy to exhaust its enemies with low-cost attacks.

"One should note that setting fires to forests in the countries of the European Union is a new tendency in Al-Qaeda's strategy of a 'thousand cuts'," the state RIA Novosti news agency quoted Alexander Bortnikov as saying at a meeting of heads of security agencies.

"This method allows (Al-Qaeda) to inflict significant economic and moral damage without serious preliminary preparations, technical equipment or significant expenses."

In linking Al-Qaeda to the deadly wildfires, Bortnikov pointed to calls to launch a "forest jihad" by various extremist websites which he said also publish detailed instructions about how and where to best carry out arson.

He said it was very difficult for special services to find and prosecute such arsonists.

Deadly blazes have swept through forest land in EU countries such as Portugal and Spain over the past few months, killing scores of people and forcing thousands to evacuate.

In its continuing campaign against the West, Al-Qaeda has vowed to "bleed the enemy to death" by resorting to inexpensive, low-scale attacks it refers to as a "strategy of a thousand cuts".