OBRENOVAC, Serbia - Here, in one of most badly flooded places in Serbia, which has seen the worst flooding in 120 years, the water has slowly begun to recede but authorities warned that the river can still surge and that the crisis was not yet over.

A power plant in Obrenovac that supplies electricity to Belgrade and a large part of the rest of the country is still at risk. Much of the town is under water and most of its population was forced to evacuate, leaving their valuables, cars and pets behind. It's a ghost town, with homes closed and shuttered.

From the helicopter we could see that the Sava River, which marks the border between Croatia and Bosnia and flows into the Danube, and several smaller rivers have turned into vast sheets of menacing brown water. That water has pushed through dikes into countless homes and farms. Today, the summery sun sparkled on the flooded land, punctuated by half-submerged apartment buildings, private homes and farmhouses.

SLIDESHOW: WORST FLOODING IN 120 YEARS

Predrag Maric, a Serbian emergency official, said Monday that the situation in Obrenovac is still critical. He said that thousands of soldiers, policemen and volunteers have managed to "defend" the power plant from the surging Sava River waters by building high walls of sandbags, the Associated Press reported.

Weather forecasters said the dry weather was expected to continue for several days.

Experts are beginning to measure the vast damage caused to homes, infrastructure, agricultural land, mines, power plants and factories. Serbian PM Aleksandar Vucic thinks it will be in the range of hundreds of millions of euros. He also praised all the help Serbia had received from U.S.

Meanwhile, Belgrade braced for a river water surge Monday that threatened to inundate Serbia's main power plant and cause major power cuts in the crisis-stricken country, the Associated Press reported.

At least 17 people died in Serbia in the five days of flooding caused by unprecedented torrential rain, laying waste to entire towns and villages in the Balkans and sending tens of thousands of people out of their homes, authorities told the AP. At least another 17 died in Bosnia, but the death toll is expected to rise as floodwaters recede in some locations, laying bare the full scale of the damage.

Three months' worth of rain fell on the Balkan region in three days. Surging water coursed through towns and villages in Serbia and Bosnia and to a lesser extent in Croatia, flowing across streets and into homes, sweeping bridges off their moorings. Sodden hills crumbled into landslides. Hundreds of buses and cars were stranded on flooded roads.

Floodwaters have also triggered more than 3,000 landslides across the Balkans. In Bosnia, the water surge disturbed land mines left over from the region's 1990s war, along with warning signs that marked location of the unexploded weapons.

The Associated Press contributed to this report.