Spain's environment minister Cristina Narbona blamed "the exceptional situation of heat and dry ground" for the fires, and warned that "the slightest negligence can turn into tragedy."

A total of 11 fires were reported on Saturday in a single central region -- Castilla and Leon -- and most of them were caused by arson, said the regional official for environmental issues, Carlos Fernandez Carriedo.

On Saturday, a pilot was killed when his aircraft struck a mountain while fighting a blaze in Medeiros, in the northwestern region of Galicia, and another firefighter died after being struck by a rock fall as his team tackled a blaze near Casavieja in the central province of Avila.

The worst of the fires raging on Sunday had already destroyed 2,500 hectares around the central city of Leon, officials said.

In all, 17 large fires, defined as those covering at least 500 hectares (1,200 acres), have erupted so far this year, officials say. That is same number as for the whole of 1995, another drought-afflicted year.

Saturday's deaths followed those of 11 experienced firefighters killed on July 17 as they were trapped by a fire that destroyed 13,000 hectares of pine forest in the central Guadalajara region.

The incident provoked a national outcry about the lack of fire fighting resources, and allegations of government mismanagement.