Fed by the highest rainfall ever recorded in the Balkans, water levels in the mighty Danube are rising, but authorities believe Europe's second-largest river will spare the already devastated region.

Serbia's Hydro Institute said Tuesday the Danube's levels will surge in coming days but should remain within the limits of flood defenses. Authorities in towns and villages along the Danube say they are watching the situation closely.

Serbia, Bosnia and Croatia have been hit by the worst flooding in more than 100 years, forcing half a million people out of their homes and leading to more than three dozen deaths.

In Serbia, the floods have been threatening the country's biggest power plants, while in Bosnia there is danger from the shifting of mine fields left over from the war.