DROSOPIGI, Greece (Reuters) - Firefighters were battling wildfires near Athens and across Greece on Saturday as the Mediterranean country sweltered under the third heatwave of the summer, with some villages and settlements being evacuated.

Explosions could be heard as huge clouds of smoke covered Drosopigi village 25 km north of Athens, where factories with flammable material are located. Helicopters dropped water and 65 firefighters battled the flames, assisted by 26 vehicles and two aircraft.

Two houses caught fire, according to state ERT television, while residents of nearby village Krioneri were instructed by authorities to leave towards Athens.

Temperatures in Greece were forecast to reach up to 44 degrees Celsius on Saturday, the Greek weather service said.

On the island of Evia, 115 firefighters and 24 vehicles were deployed to put out fires, assisted by six aircraft and seven helicopters, but strong winds were hampering their efforts. Residents of the island's Triada area were told to be ready in case they needed to leave.

The fire on Evia is the latest in a series of bushfires stoked by strong winds and dry conditions this month.

On the island of Kythera, authorities evacuated the villages of Aroniadika, Pitsinades and Aryoi. In the area of Messinia, west of Athens, residents of the Kryoneri and Sellas villages were also told to leave.

These sites were on a list of Greek regions on high alert for wildfires due to record-breaking temperatures and strong winds due on Saturday.

Tourism is a key earner in Greece, and the fires have hit since the start of the peak summer holiday season early in July.

Greece and other Mediterranean countries are in an area dubbed "a wildfire hotspot" by scientists, with blazes common during hot and dry summers. These have become more destructive in recent years due to a fast-changing climate, prompting calls for a new approach.

(Reporting by Stamos Prousalis; Writing by Daria Sito-Sucic; Editing by Jan Harvey)