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 homes, sometimes reaching the second floors, sending people climbing to rooftops to await rescue.

Hundreds were also evacuated in Croatia, where authorities said that 25 people had already died. 

Thousands of homes have been left without electricity or drinking water and major power stations have been threatened by the waters.

Landslides triggered by the floods also raised the risk of injury from landmines left over from Bosnia’s 1992-95 war after warning signs were swept away.

Three months’ worth of rain fell on the Balkans in three days last week, creating the worst floods since records began 120 years ago.

Almost a third of Bosnia is submerged, with houses, roads and railway lines swamped. 

Security Ministry spokesman Admir Malagic said that about a million people — over a quarter of the population — lived in the affected area.

“Bosnia is facing a horrible catastrophe,” said Bosnia and Herzegovina joint-President Bakir Izetbegovic. 

“We are still not fully aware of the actual dimensions of the catastrophe. We will have to take care of hundreds, perhaps thousands of people.”

In the Bosnian town of Bijeljina, some 10,000 people were evacuated on Saturday after the Sava River overwhelmed flood defences.

The rain caused nearly 300 landslides in Bosnia, burying dozens of houses and cars and further complicating relief efforts.