BBC News, Belgrade
Serbia is bracing itself for the highest river levels in 25 years as flood waters from central Europe make their way south.
The army has been called in to help with the effort
The situation is at its worst in the northern province of Vojvodina, near Hungary, where flooding has driven hundreds of people from their homes.
For days soldiers and civilians have been battling a natural enemy.
In northern Serbia they have been building barricades of sand bags to keep the ever rising waters at bay.
The rivers have been swelling to a peak which has yet to come.
The Danube, the Sava, the Tisa, the Tamis and their tributaries have all flooded.
It is the same water that last week ravaged parts of Hungary, Germany, Austria and the Czech republic.
The areas around Serbia's second largest city Novi Sad are particularly vulnerable, but low lying parts of the capital, Belgrade, have also been hit.
It is not just the human cost of flooded homes that is a worry, there is an environmental concern as well. Sewage and industrial pollution may be washed back into the rivers when the waters fall.
Scores of Belgrade's popular riverside bars and restaurants have already closed and they will remain so for some time. More rain is forecast.