CANELA, Portugal, July 29 (Reuters) - More than 1,300 firefighters battled to control three major wildfires in central and northern Portugal on Tuesday, backed by dozens of water-dropping aircraft, as authorities put much of the country on maximum fire alert after weeks of sweltering weather.

The Civil Protection Service in the Arouca region, about 300 kilometers north of Lisbon, evacuated dozens of villagers from their homes and closed a popular tourist attraction. The largest fires have been raging in the area since Monday.

Further north, a forest fire has been burning since Saturday in the Peneda-Gerês National Park near the Spanish border, producing thick smoke that has enveloped nearby villages and prompted residents to stay indoors on several occasions.

Spain has sent several water-dropping planes to help control the fires in the area.

Three wildfires broke out in Spain's Castile and Leon region early Tuesday, with the most intense near Avila, about 100 kilometers (62 miles) west of Madrid. Residents of the town of Mumbeltran were ordered to stay indoors due to the smoke.

The Mediterranean region commonly experiences hot, dry summers, but extreme heat waves have contributed to devastating wildfires in recent years amid rapidly rising temperatures around the world.

(Prepared by Noha Zakaria for the Arabic edition - Edited by Marwa Salam)