The soldiers were to help monitor parts of the blaze which are already under control in order to enable the 250 firefighters to tackle the more active fronts of the fire, rescue workers said.

Firefighters said the steep slopes of the mountains, combined with strong winds and high temperatures, were complicating the battle against the fire, which erupted on Sunday afternoon near Silvares, 260 kilometres (160 miles) north of Lisbon.

Temperatures are expected to soar to 35 degrees Celsius (95 degrees Fahrenheit) on Tuesday, with winds of up to 40 kilometres (25 miles) an hour.

"The wind would be pleasant if you were on a beach, but not if you are battling a fire," the director of Portugal's National Rescue Centre, Nuno Costa, told private radio TSF.

"We predict it is going to be a complicated, hard day," he added.

The firefighters, who came from all over the country, were equipped with four helicopters and six planes, including two which arrived from neighbouring Spain on Monday following a request for help from Portuguese authorities.

Telephone and electricity services, which were temporarily cut off to the 70,000 residents of the nearby city of Castelo Branco because of the blaze on Monday, have since been restored, the Lusa news agency reported.

Officials said they suspected the fire had been started deliberately.

It is the second big blaze which Portugal has faced this month. Last week a fire which raged for two days destroyed some 4,000 hectares (9,900 acres) of pine and eucalyptus forest in central Portugal.

Forests cover roughly one-third of Portugal and forestry accounts for 11 percent of the nation's exports, but each summer thousands of trees are destroyed by fires.

There were some 25,000 forest or brush fires last year in Portugal which burned almost 120,000 hectares (296,400 acres) of land, according to forest service figures.

Environmentalists argue a large number of fires could be avoided if the government did more to clear forests of overgrown areas which can easily ignite during the dry summer months.

Officials estimate that less than 10 percent of all fires are caused by natural causes. Firefighters blame the vast majority of blazes on either negligence on the part of campers and farmers or arson.

TERRA.WIRE