At least 20 people are confirmed dead in Serbia and Bosnia because of the worst flooding in the Balkans in over a century.

Seven bodies were recovered from flooded homes in Obrenovac, Serbia, Saturday as the army rushed to the rescue of hundreds of people stranded in a school, Reuters reported.

Soldiers used amphibious vehicles to navigate streets in Obrenovac that were buried under six to 10 feet of water. Soldiers struggled to get to a school in the city, which is 18 miles southwest of the Serbian capital of Belgrade, to rescue around 700 people who were stranded on the top floors of an elementary school.

Other stranded citizens climbed onto balconies or the roofs of their homes. The army eventually rescued the citizens by taking them into small boats and seeking dry ground.

The town, which has a population of around 30,000 people, was hardest hit by the flooding, which was caused by abnormally heavy rainfall. The amount of flooding is at an unprecedented level, higher than it has ever been since records began 120 years ago.

The flooding caused 95,000 homes to lose power and brought power capacity down by 40 percent.

Prime Minister Aleksandar Vucic said three are confirmed dead, but the death toll cannot be confirmed until waters recede.

At least 11 are confirmed dead in Bosnia with six bodies recovered on Saturday in the northern town of Doboj.

In the town of Sabac in western Serbia, thousands of volunteers worked with soldiers and firefighters to build sandbags to try to stem the rising waters.

Authorities are evacuating 10,000 people in the Bosnian town of Bijeljina, and more than 15,000 have been evacuated to Serbia.

Rain continued to fall on Saturday in the region, and more rain is forecast for Sunday.

"Now we have to sit and wait, to wait for that next wave and to hope," Vucic told a joint news conference with Bosnian Serb leader Milorad Dodik.

"We left behind the car, motorcycle, tools, all our furniture, valuables," said Dragana Ilic, an Obrenovac resident who was evacuated to a shelter in Belgrade.

"We just grabbed our mobile phones and left," Ilic said. "All our IDs were left behind. The whole house is under water."

Around 1,000 people were also evacuated from Zeljezno Polje in central Bosnia, where hundreds of homes were decimated in landslides.

The flooding of the Danube, Kolubara and the Sava rivers brought down power lines and transformer stations and soaked coal depots. It also caused a fire inside the Kolubara power complex, which has been closed down since Thursday.