Montenegro has asked Nato to send two firefighting planes to help contain raging wildfires, according to state TV.
The report said the Western military alliance is checking which member country could provide the planes.
Wildfires have engulfed the Lustica peninsula amid strong winds and dry weather. More than 100 people have evacuated the areas around the coastal tourist town of Tivat.
Smaller fires also have been reported along the Adriatic coast.
Montenegro joined Nato earlier this year, defying Russia and pro-Russian opposition at home.
In Croatia, authorities said firefighters battled through the night to contain raging wildfires that threatened the key port of Split on the Adriatic coast.
Parts of the coastal town were enveloped in thick smoke on Tuesday after flames reached suburban areas on Monday evening. Residents have joined firefighters to defend the houses and stop the fire from spreading.
Emergency services said 80 people have been lightly injured. They added that the situation had improved in the morning after firefighting planes took off and the wind slowed down.
Meanwhile, hundreds of firefighters were working to extinguish a forest fire about nine miles from the French Riviera city of Nice, as unusually hot and dry weather hits much of France.
Jean-Gabriel Delacroy of the Alpes-Maritime regional administration said the fire is "under control" but not yet over after breaking out on Monday night.
Speaking on broadcaster Francetvinfo, Mr Delacroy said three firefighters were lightly injured by the blaze, which consumed about 300 acres of forest and reached the town of Castagniers, inland from Nice.
No homes have been damaged so far, he said.
Whipped up by Mediterranean winds, fires in recent days have also hit Provence and Corsica during the high summer tourist season.