The National Observatory in Athens said the warmest temperature recorded was 45.8C in the Peloponnese region of Messinia.

In Athens, the highest temperature in parts of the capital was 42C, also recorded in the main port of Piraeus.

Officials once again modified the opening hours of the Acropolis, the country's top archaeological site, for the safety of visitors and staff.

The monument was shut from midday to 5:00 pm -- the hottest part of the day -- in line with usual safety rules.

The Greek weather agency EMY modified a warning note to reflect that temperatures would begin falling after Monday July 28, instead of on the weekend as it had previously reported.

Northern winds are expected to pick up later Friday, raising the risk of fires, EMY said.

A wildfire earlier this week destroyed more than 2,800 acres (1,130 hectares) of forest and grassland near the mountain village of Feneos in the Peloponnese.

It was apparently started by two workmen using welding equipment near a forest.

Over half of the area affected was a pine forest that cannot regenerate, the National Observatory said.

On Friday, a fire burning near the city of Kilkis in northern Greece forced the evacuation of a university, homes and businesses, the fire service said.

A high of 44C was expected in Greece on Saturday, with a maximum of 42C forecast in Athens, the agency said.

In neighbouring Albania, there were 10 active fires including one in Delvina, near the border with Greece.

Another fire in Kakavia, near the border crossing with Greece, was brought under control on Thursday.