A wildfire that broke out just north of Athens has spread to multiple settlements, forcing residents to flee their homes and a warning has been issued to tourists.

By Sunday, the fire had reached Mount Penteli, just north of the Greek capital, sending thick brown smoke clouds over the city.

Smoke billowing over the hills north of the city could be seen by passengers landing and departing from Athens airport. Flights are continuing as scheduled, but 80% were delayed yesterday.

The smoke has reportedly also reached the island of Aegina to the south of the city.

Residents and tourists have been advised to keep windows closed in some parts of Athens, while more than 400 firefighters, 17 waterbombing planes and 13 helicopters continue to fight the blace.

The fast-moving fire, which has been fuelled by hot, windy conditions, has destroyed homes, vehicles and trees.

City Protection in Greece has issued an emergency warning to residents of nine areas, advising them to be on high alert. Some, including those in Marathon, the birthplace of the Olympics just east of Athens, have been ordered to evacuate.

Image is a stock photo of a wildfire north of Athens in 2021