Chancellor Angela Merkel pledged 100 million euros in emergency aid for flood-ravaged areas on Tuesday as surging waters that have claimed at least 11 lives and forced tens of thousands of evacuations across central Europe bore down on eastern Germany.

Heavy rains have turned vast regions into lakes, cut off villages, severed transport links and left historic city centres under muddy brown water. The inundations have also brought back dark memories of devastating floods that killed dozens in 2002.

The largest volumes of water have travelled down two of Europe's great river systems: the Danube, which runs from Germany through Austria and central Europe into the Black Sea, and the Elbe, which flows from the Czech Republic through eastern Germany into the North Sea.

Merkel travelled by helicopter over the flood zone and visited three impacted areas, starting in Passau, Bavaria, where the Danube meets two other rivers and peaked late Monday at 12.9 metres (42 feet), the highest level since 1501.

The chancellor vowed the emergency cash would be disbursed in an unbureaucratic way because "what's important now is that the aid quickly reaches the people". Property damage in Passau alone was estimated at 20 million euros ($26 million) by the city mayor.

Some people have paddled canoes down flooded streets in Passau, where drinking water, power and phone services were cut. Elsewhere stranded residents were evacuated from their soggy homes by rescue personnel using inflatable boats.

"The damage and the loss of income is a long-term matter. And that's why our support will not cease," said Merkel, who faces an election in less than four months and was later photographed helping to fill sandbags.

Across the region, the official death toll rose to 11 as Czech emergency services recovered the body of a man from the swollen Male Labe river in the northern Krkonose mountain range, near the border with Poland.

The deluge killed seven others in the Czech Republic, including a woman who was hit by an uprooted tree as she walked her dog. Two others died in Austria and one in Switzerland. Several more people were missing.

Across much of the swamped region, rail, road and river traffic links were cut, crops destroyed, schools and factories closed and hospitals evacuated.

In Prague, the flood water hit its highest level on Tuesday after inundating the city centre, displacing more than 8,000 people and forcing a night-time operation to move animals in the city's zoo to higher ground.

Tourists mingled with locals on Prague's bridges, taking pictures of the high water, sandbags in the doorways, anti-flood defences and the 14th-century Charles Bridge which remained closed to the public.

Prague mayor Tomas Hudecek bemoaned "an excessive surge in flood tourists" amid reports that some had attempted to dismantle anti-flood defences to take home as souvenirs.

Prague has installed anti-flood walls along 17 kilometres (10.5 miles) of riverfront, said fire brigade spokeswoman Nicole Zaoralova.

The mass of water was headed downstream to eastern Germany, where cities on the Elbe, including Dresden and Magdeburg, scrambled to prepare for potentially massive floods.

In Magdeburg, authorities declared a state of emergency and said they expected the river, normally at two metres, to rise to almost seven metres -- higher than in 2002.

In all, Germany deployed some 43,000 fire fighters and 4,000 troops in four states, securing dykes with sandbags, and providing food, shelter and clothes for displaced people.

Transport Minister Peter Ramsauer expected the damage to German road and rail infrastructure to reach hundreds of millions of euros.

Several events were cancelled, including a music festival dedicated to Baroque composer Georg Friedrich Handel planned for June 6-16 in the eastern city of Halle.

President Joachim Gauck declared that "the fate of the victims moves me ... I'm glad to hear that they are standing united in solidarity and determination in these hours and are receiving a lot of assistance and support."

Austria mobilised more than 20,000 firefighters, police and rescue workers and 800 soldiers in areas along the Danube, while Chancellor Werner Faymann promised compensation for the victims without specifying an amount.

Authorities predicted that waters would peak overnight in the Wachau valley some 100 kilometres (60 miles) west of Vienna.

In the Austrian capital itself, water levels may surpass those of 2002 in the next day or two.

Downstream in Hungary, Prime Minister Viktor Orban declared a state of emergency and mobilised more than 20,000 emergency and military personnel.

The peak of the Danube flood is expected in western areas Wednesday and in Budapest by the weekend.

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