BERLIN - The swollen Elbe river rose to record levels in parts of northern Germany, while in Serbia authorities declared a maximum alert as the Danube edged up to the danger zone.

But German authorities said the worst of recent flooding would soon be over, and a Serbian official said there was "no need to panic."

The Danube rose to 7.34 meters (24 feet one inch) at the frontier between Serbia and Hungary, its second highest level since 1888.

The record highest level of 7.78 meters in 1965 caused catastrophic flooding in the Voivodine province.

Vladimir Milosev, a city official in the provincial capital Novi Sad, told local media, "we are in a state of maximum alert along the dykes, but for the moment, no negative consequences have been recorded. There is no need to panic."

In Belgrade, authorities warned of possible flooding in low-lying areas of the city because of rises in the level of the Danube and a tributary, the Sava.

In the German state of Schleswig-Holstein, the Elbe had risen to 9.10 metres from its normal level of five meters and was expected to rise another 10 centimetres, a local authority spokesman said.

"We have the situation completely in hand," he said, adding that measures had been taken in the city of Lauenburg to protect historic buildings.

The river has flooded cellars and threatened severe damage to 16th and 17th century houses in the city.

Upstream at Hitzacker, most of the old town was under water after the river swelled to almost three times its normal level.

It was 12 centimetres deeper early on Sunday than in 2002 when northern and eastern Germany suffered devastating floods, but authorities said they expected it would not go beyond the current level of 7.6 metres.

"We are assuming that we have reached the limit," a spokeswoman for the city said, adding that the water was expected to start receding on Monday.

Authorities believed it would take around 12 days to drain away.

Some 3,200 rescue workers and soldiers have been rushed to the area in recent days to place thousands of sandbags along the river to reinforce dykes.

Chancellor Angela Merkel visited Hitzacker on Sunday before taking a helicopter flight over nearby affected regions.

"The situation seems exceptionally threatening," she told reporters.

The Elbe flooded parts of the eastern state of Saxony earlier this month as snow melted at the beginning of spring. It swelled to more than three times its normal level before receding.

The historic state capital of Dresden escaped damage, unlike in 2002 when it was badly hit by the floodwaters.

But authorities said they were concerned about the situation downstream in Prignitz, in Brandenburg state, because, though water levels were receding, a strong wind was putting pressure on dykes.