Firefighters are battling through thick smoke as wildfires threaten thousands in Greece, with the worst blazes tearing through the tourist islands of Crete and Paros.

A violent blaze has killed two firefighters and forced 8,000 holidaymakers and locals to evacuate in Crete.

Authorities have declared a state of emergency in the Rethymno region, where the inferno has been raging since Thursday.

On the island of Paros in the Aegean Sea, a fire that broke out Tuesday has also prompted evacuations. 

A third firefighter died in the Peloponnese on the Greek mainland.