Packed into buses, boats and helicopters, and each carrying nothing but a handful of belongings, tens of thousands of people fled their homes in Bosnia and Serbia on Saturday to escape the worst flooding in a century.

Rapidly rising rivers surged into houses, sometimes reaching the second floors, sending people to rooftops for rescue.

Hundreds were also evacuated in Croatia.

Authorities said 25 people have died but warned that the death toll could rise. Tens of thousands of homes were left without electricity or drinking water.

Landslides triggered by the floods also raised the risk of injury or death from land mines left from Bosnia’s 1992-95 war. The landslides swept away many of the carefully placed warning signs around the minefields.

Three months’ worth of rain has fallen on the region in three days this past week, creating the worst floods since records began 120 years ago.

Observed from the air, almost a third of Bosnia, mostly its northeastern corner, resembled a huge muddy lake, with houses, roads and rail lines submerged. A spokesman for Bosnia’s Security Ministry said about a million people — more than a quarter of the country’s population — live in the affected area.

Officials in Bosnia say 17 people died and more bodies could be found as water recedes from dozens of cities.

In Serbia, eight deaths were reported.

— Associated Press