One fire was threatening the Campidouro camping ground near Medas, 30 km (20 miles) south of Porto where 100 firefighters were fighting the blaze.

Another major blaze forced the closure of the highway between Lisbon and Porto and consumed more than 1,000 hectares of forest, firefighters said.

In the region of Albergaria-a-Velha, ravaged for two days by fires, fire fighters were battling to prevent a new outbreak with the aid of water-dropping helicopters.

A total of 1,348 firefighters using 436 vehicles and 22 water-dropping aircraft were mobilised to fight the fires throughout the country.

The national agency for the prevention of fires warned that the situation remained extremely dangerous in seven areas in the north and center because of the severe or extreme drought affecting virtually the entire country.

The national water institute said Portugal had seen no substantial rainfall since October.

In 2003, catastrophic fires resulted in 20 deaths and swallowed up 420,000 hectares of forest and vegetation.