(CNN) -- Severe flooding across Serbia has prompted the evacuation of at least 16,300 people -- including 1,100 whisked away on helicopters -- the government said Saturday.
A spokesman for the Interior Ministry confirmed there have been at least 15 deaths in Serbia and another five in neighboring Bosnia-Herzegovina. Unconfirmed reports put the numbers even higher.
It's the worst flooding Serbia has seen since the country began keeping records 120 years ago, according to meteorologists.
The catastrophic weather has prompted authorities to declare a state of emergency in Bosnia-Herzegovina, according to a government statement. Bosnian authorities say the flooded town of Maglaj received the average rainfall for a two-month period in less than two days.
Speaking at a press conference, Serbian Prime Minister Aleksandar Vucic said that the situation in his country is "difficult," but that Serbia is prepared for the next wave of floods.
More rising waters are expected Sunday evening near Sabac, a city in western Serbia near the Sava River. Vucic said that Sabac is well fortified and that authorities had done "everything that could be done."
The Prime Minister pointed out that a dam 7.3 meters tall (24 feet) has been erected, but that the current level of the Sava River is over 6.3 meters -- a historic high. The river is expected to rise. He warned that it is difficult to predict what will happen if the river reaches 6.8 meters, or slightly more than 22 feet.
Rescuers in the hard-hit town of Obrenovac, 30 kilometers (about 19 miles) southwest of Belgrade, have recovered the first bodies of flood victims, according to Vucic. He expressed concern over how many may eventually be found once waters subside. Authorities estimate that 90% of the town has been flooded.
The Prime Minister thanked the many countries that have already come to Serbia's aid. He was especially grateful to members of the Russian special forces, highlighting one member who swam 200 meters in cold water to save several people. According to Finance Minister Dusan Vujovic, more than 10,000 troops have already been involved in rescue and assistance operations.