ATHENS, Greece — Authorities in Athens closed the Acropolis to visitors for several hours Tuesday due to high temperatures as work restrictions remained in effect in other parts of Greece.

The closure lasted from 1 p.m. to 5 p.m. (1000 GMT to 1400 GMT), the Culture Ministry archaeological service said.

Mandatory work breaks were imposed in several other regions, mostly on islands and parts of central Greece, where temperatures exceeded 40 degrees Celsius (104 degrees Fahrenheit). The measures started Monday for outdoor workers. Workplaces that don’t comply face a 2,000 euro ($2,350) fine per worker.

Authorities said the risk of wildfires, already at “very high” across the eastern mainland, is expected to increase during the week.

Elsewhere in Europe, a wildfire in northeastern Spain burned roughly 3,000 hectares (7,400 acres) on Tuesday with authorities ordering some 18,000 people in Tarragona province to remain indoors.

Other parts of Spain were on high alert for wildfires after experiencing record-high temperatures in June.