Hungarians are preparing for what the prime minister has predicted will be the country's worst floods ever as the Danube is expected to reach record levels.
Thousands of volunteers joined soldiers and emergency workers to defend the historic capital Budapest and other areas.
More than two million sandbags have been stacked at 16 high-risk locations along the 760 kilometres of the Danube River rushing out of Germany and Austria on its way to the Black Sea.
Some 3000 volunteers, 6000 emergency service personnel, and the entire Hungarian army have been mobilised across the country, AFP reports. More than 16,000 army, police and civil reservists were also on standby.
In the northern Romai district of the capital, Roma and the Hungarian National Guard came together in an improbable partnership to fill sandbags.
The low-lying Romai area is particularly exposed as the Danube suddenly widens there after curving sharply south from the Slovakian border.
Mayor Istvan Tarlos warned on Thursday if the water rises above 8.75 metres 55,000 people would have to be evacuated.
