Fire crews outside Athens scrambled Monday to exploit a lull in high winds, but the flames spread further and dozens of nuns had to be rescued from a convent threatened by one blaze, officials said. The massive wildfires broke out Friday and have razed about 58 square miles (37,000 acres or 15,000 hectares) of forest and brush, damaged or destroyed scores of homes and forced thousands to flee outlying areas of the capital. At least five people were being treated for burns and several dozen had reported breathing problems, but none of the injuries is serious, Health Ministry officials said. At first light Monday, 17 water-dropping planes and helicopters resumed operations, swooping over flames near populated areas. "There are some signs of optimism but no letting up of the firefighting effort. We have a chance to contain this nightmare that has burned the city's main forest area," Athens regional governor Yiannis Sgouros said. "After this, we will assess the extent of this catastrophe - how many homes were destroyed, and how much damage was done." Winds were expected to pick up later Monday. Fires raged, meanwhile, at the coastal town of Nea Makri and nearby Marathon - site of one of ancient history's most famous battlegrounds - to the northeast of the capital, and at Vilia to the northwest. At Nea Makri, a blaze was tearing down a hillside toward houses, and a dozen nuns were rescued from a nearby Christian Orthodox convent threatened by fire. Volunteers, clutching branches and with water-soaked towels wrapped around their necks, beat back the flames as the evacuation took place. Elsewhere, residents defended homes, soaking their front yards with garden hoses and buckets of water. Fires continued to threaten the ancient fortress town of Rhamnus, home to two 2,500-year-old temples. Up to 2,000 firefighters, soldiers and volunteers are involved in fighting fires stretching more than 30 miles (50 kilometers) northeast of Athens. Aircraft have been sent from France, Italy and Cyprus to join in the effort, with more help expected from other countries. Officials have not said what started the fires - the worst since deadly blazes ravaged southern Greece two years ago, killing 76 people. Hundreds of forest blazes plague Greece every summer and many are set intentionally - often by unscrupulous land developers or animal farmers seeking to expand their grazing land. Six major fires were burning early Monday across Greece, including blazes on the islands of Evia and Skyros in the Aegean Sea and Zakynthos in the west.