PRAGUE - Swollen rivers and floodwaters forced thousands of people across Central Europe to leave their homes and there were fears melting snow could make matter worse.

In the Czech Republic the death toll from the floods rose to at least four after police announced Sunday they had found the body of a drowned pensioner in the centre of the country. A further two people have lost their lives in neighbouring Slovakia.

A fifth of the historic city of Olomouc, in the east of the Czech Republic, was inundated when an embankment holding back the raging Morava gave way during the early hours of Sunday.

In Hungary, Budapest's mayor urged the government to declare a state of emergency for those parts of the city most threatened by the Danube and ban traffic on the river.

Olomouc city council ordered the evacuation of a further 2,000 people Sunday afternoon although the danger to the city of 100,000 inhabitants appeared to be subsiding with the embankment repaired and the river level stabilising.

In the south-east, the South Moravian governor ordered 4,000 people to quit a handful of villages menaced by a 500-hectare (1,235 acre) lake on Sunday afternoon.

The lake, fed by local rivers, has been developing on low lying farmland over the last days.

In the north of the country, streams and rivers continued to swell the Elbe which climbed to 8.46 metres (28 feet), more than four times its normal level, by noon Sunday with no respite expected before Monday.

The regional authority declared a state of emergency for the entire length of the river from 40 kilometres north of Prague to the German border on Saturday.

Flood emergency situations had been announced by half of the country's 14 regional authorities by the end of Saturday.

Authorities warned that higher temperatures, thawing snow which still carpets mountains across the country, could dramatically worsen the situation. Prime Minister Jiri Paroubek was cautious on Sunday.

"Everything depends on weather conditions and here there is still a lot of uncertainty," he told public television.

In Hungary, the highest level flood alerts were in force on 600 kilometres (370 miles) of river in the country on Sunday with the number of evacuees mounting to 3,704, according to the national disaster prevention authority.

The worst affected areas were in the north of the country, bordering Slovakia. Road and rail transport across the country was disrupted.

In Slovakia, river levels remained critical although the risk appeared to be easing. A state of emergency was declared Saturday at Trtice in the south-west of the country after the Cierna Voda reached a dangerous level.

In Austria, the level of the Danube and of many rivers in the north of the country remained at a critical situation over the weekend without, however, requiring people to flee their homes.

The Czech Cabinet was due to hold an emergency meeting to assess the flood risk and what new measures could be taken to help stricken areas.