France and Greece are sending firefighting planes to Italy after Rome asked for help to tackle wildfires in Sardinia.
Paris and Athens are deploying two forest firefighting planes each after Italy activated the EU Civil Protection Mechanism.
"For several hours a large area in the province of Oristano has been on its knees due to a devastating fire," Luigi di Maio, Italy's Foreign Minister, wrote on Facebook on Sunday
"There are hundreds of people evacuated and the entire area, including housing, has been burnt in flames and managed," he added.
At least 355 people have also been evacuated from their homes.
Regional authorities said that 7,500 firefighters have been mobilised as well as 20 aircraft including seven Canadairs and 13 helicopters.
Christian Solinas, President of the Sardinia region, described the wildfires as "an unprecedented disaster."
"Ten thousand hectares of vegetation destroyed, businesses and houses burned, livestock killed," he wrote in a statement.
The region has declared a state of emergency and called on the government to deliver "immediate financial support to repair the damage and help the affected communities to restart."