Prague - Authorities across eastern Europe declared flood alerts on Thursday amid fears that rivers swollen by a sudden spring thaw could spill over in a repetition of the disastrous east European inundation of 2002.

Six people in the region, including two children, were reported killed by the raging waters and a teenager was reported missing in Romania. In Eastern Slovakia, a four-year old Roma boy fell into a stream and drowned and a 61-year-old man was found drowned at Modra in the southwest, the authorities said.

In the Czech Republic officials confirmed a five-year-old boy had been swept away near the town of Trebic two days earlier. Czech broadcaster CT1 added that a man had died of a heart attack as he tried to save belongings from his flooded house and that two people had drowned in their car near Terezin.

The situation was at its most serious in Moravia in the southeast of the Czech Republic, where the Vranov dam was overflown by the swollen Dyje river, a Danube tributary which was surging at 30 times its normal level.

Some 10,000 people in and around the town of Znojmo were evacuated on Wednesday evening because of the threat from the Dyje, which began to inundate buildings late on Thursday. Soldiers were drafted in to help with the flood preparations.

A emergency situation was declared late on Thursday by the governor of the South Bohemia region, where the ever-swelling Luznice river threatened the areas around two of the biggest towns, Tabor and Jindrich Hradec.

The levels of the Elbe, Danube, Morava and Vltava rivers, as well as other rivers crossing the Czech Republic, Slovakia, Poland, Austria and Hungary, have sparked flood alerts across the region.

However, fears of a flood disaster in eastern Germany faded after the environment minister of Saxony, Stanislaw Tillich, said the situation was not potentially "catastrophic."

Nevertheless, officials said the Elbe river had reached worrying levels. In the city of Dresden, which was severely damaged by the 2002 floods, the level of the Elbe was reported three times higher than normal at 6.5 metres (21 feet). But this was still well short of the level reached four years ago.

Television news channels showed people standing up to their waists in water in towns along the river.

The Czech hydrological office warned on Thursday that the danger of severe flooding in the south of Moravia and around Zlin, as well as a dozen other sites across the country, would last until Saturday. Rain, predicted on Friday, threatened to worsen the flood risk, especially in the south and centre of the country.

The highest, level-three, flood alerts were declared at 78 locations in the Czech Republic on Thursday morning. That number fell to 44 by the end of the afternoon.

Flood protection barriers in the capital, Prague, were completed on Thursday morning. The city, where the catastrophic August 2002 floods are still fresh in many memories, remained on a level-two alert Thursday.

In Germany, a state of alert was announced in the eastern region of Saxony, after the Elbe reached a critical level, local authorities announced.

At Pirna, around 20 kilometres (12 miles) from the Czech frontier, people living near the river were evacuated as a preventive measure. At Bad Schandau, around 1,000 people already left their houses on Wednesday night.

In Bavaria, the area around Passau was on flood alert due to the high level of the Danube.

Flood alerts were announced for a number of rivers in Hungary. A section of the lower embankment of the Danube in Budapest was closed to traffic due to the high water level.

Alerts were also put into in effect in the south, west and parts of central Poland on Thursday but only local cases of flooding were reported.

Polish authorities in the Silesia region, in the south of the country, already declared a flood alert on Tuesday on fears that the river Oder would overflow its banks.

In Slovakia, the highest level flood alert was declared at many sites across the country, especially in the west where the Morava and Danube rivers continued to rise.

A spokesman for the fire service said that around 123 villages, 600 houses and around 2,000 hectares of agricultural land were flooded.

Storms also hit Romania where a teenager was reported missing on Thursday and around 50 houses and dozens of hectares (acres) of agricultural land were inundated at Bistrita-Nasaud in the north of the country and Mures in the centre of the country.