At least 40 people have died in Serbia and Bosnia during flooding caused by unprecedented torrential rain. The death toll is expected to rise as floodwaters start to recede, exposing the scale of the damage. Three months' worth of rain fell on the region in three days, producing the worst floods since rainfall measurements began 120 years ago.

The swollen River Sava is threatening the Nikola Tesla power plant, which supplies electricity to half of Serbia and most of Belgrade. It is located in Obrenovac, the worst-hit town where 7,800 people have been evacuated from their homes. Some 2,000 people are still believed trapped in top floors of buildings, without power or phone lines.

A man walks through flood water in the town of Obrenovac, SerbiaReuters
Residents of the Serbian town of Obrenovac are evacuated on an amphibious vehicleAFP
Serbian rescue workers evacuate an elderly man from the flooded town of ObrenovacAFP
People taker cover in their apartments as they wait to be evacuated in the flooded town of ObrenovacReuters
Serbian Army soldiers evacuate a boy from a flooded house in the town of ObrenovacReuters
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A Serbian Army soldier rows a boat as he searches for people to be evacuated in the town of ObrenovacReuters
A man carries a dog after being evacuated from a flooded house in the town of ObrenovacAFP
A Serbian rescuer carries an elderly woman out of her flooded house in the village of ObrezAFP
A rescuer carries a dog on a flooded street in the village of Obrež, near the central Serbian town of VarvarinAFP
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Volunteers pass sand bags along at the entrance of the former Zorka chemical plant in Sabac, 100 kilometres west of BelgradeAFP
Evacuees from the Serbian town of Obrenovac shelter in a hall in BelgradeReuters
Children's shoes donated to evacuated people from the Serbian town of Obrenovac are seen at a shelter in BelgradeReuters

Surging water has coursed through towns and villages in Serbia and Bosnia and to a lesser extent in Croatia.

In Orasje, a Bosnian border town, the emergency force commander, Fahrudin Solak, said the decaying corpses of drowned farm animals now represent a major health risk.

The Bosnian Army said it had 1,500 troops helping on the ground. But many bridges have been washed away, leaving communities dependent on airlifts.

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An aerial view of a flooded area near the northern Bosnian town of Brčko, on the Sava RiverAFP
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An aerial view of flooded fields on the outskirts of Orasje in northern Bosnia, on the border with CroatiaReuters
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An aerial view of the town of Orasje, flooded by the Sava RiverReuters
A woman and her children arrive by European Union Force helicopter after being rescued from the flooded Bosnian village of SericiReuters
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Villagers stand on the edge of a bridge that collapsed after flooding, near Orasje, BosniaReuters

Large parts of eastern Croatia are underwater too, with several villages cut off and hundreds still fleeing the flooded zone in boats and trucks. Refugees were being housed in sports halls and schools, and aid centers were set up to distribute medicine, food, blankets and clothing.

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Floodwaters swirl around cars in the village of Gunja, in eastern CroatiaAFP
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A man, woman and two dogs are evacuated on a boat over flooded streets in the village of Gunja, in eastern CroatiaAFP