ZAGREB, Croatia (AP) — Croatian authorities say firefighters are battling a wildfire in the south of the country's Adriatic coast that has spread across the border from neighboring Montenegro.

They said Thursday that firefighting planes have been trying to contain the blaze and prevent it from spreading any further.

Both Croatia and Montenegro have faced a series of wildfires along the Adriatic coast amid high summer temperatures and dry weather.

In Croatia, flames have reached the key port of Split this week, causing panic. In Montenegro, at least 100 people had to evacuate in an affected tourist area.

Authorities have expressed fears of more wildfires with a new heat wave expected this weekend.