The Balkans braced for swollen rivers to reach new peaks on Monday, piling up misery after the worst floods in a century killed 45 people and sent tens of thousands fleeing for their lives. Muddy waters from the Sava River have submerged houses, churches, mosques and roads in Bosnia and Serbia after record rainfall wreaked havoc across the central European region and the waterway was expected to swell to new highs on Monday. Some 50,000 people have been evacuated in Bosnia and Serbia, with an additional 15,000 in Croatia. With some towns completely cut off by the torrents, fear rose that the death toll could rise significantly once rescue teams were able to move in. "What happened to us happens once in a thousand years," Serbian Prime Minister Aleksandar Vucic said on Sunday. Rescuers told of wrenching scenes as they finally reached cut-off villages, with dozens of people huddling at the highest houses with no water or food. Besides the flooding, the worst rainfall since records began in the late 19th century, also caused landslides that brought more destruction, prompted landmine warnings and closed numerous border crossings. The dikes built by thousands of volunteers along the Sava River and around the Nikola Tesla power plant managed to hold overnight, Serbian state-run RTS television reported. The plant, which produces some 50 percent of Serbian electricity, was surrounded by water. Humanitarian aid, technical equipment and teams from Russia, the European Union, the United States and neighbouring Montenegro and Macedonia were pouring in, authorities said.