As the last votes in regional and Senate elections in the Czech Republic were counted Saturday, the opposition Social Democratic Party looked as if they had issued a heavy blow to Prime Minister Mirek Topolanek, reports dpa.
"The voters want change," Social Democratic leader Jiri Paroubek told the public broadcaster Czech Television.
The Social Democrats took all 13 regions where voting took place, their first such success since 2000.
Topolanek's right-wing Civic Democratic Party has governed in 12 of those regions for the last four years.
Prague, officially also a region, elects its government in municipal elections that last took place in 2006.
The Social Democrats also did well so far in the Senate elections, in which voters were picking 27 of 81 senators.
The party won one seat and is headed for a runoff next Friday and Saturday with its candidates leading in 19 of the remaining 26 districts.
"I would like to congratulate the winner ... this is a defeat," Topolanek told the station, calling the loss "a toll for governance".
The Topolanek-led centre-right government has introduced several unpopular belt-tightening public spending measures such as direct fees in healthcare, for which analysts expected him to pay dearly in the vote.
The heavy losses, just 10 weeks before the Czech Republic takes over the European Union's rotating presidency, is likely to shake up Topolanek's position as a party leader and possibly as a premier.
Paroubek reiterated his party's intention to call for a vote of no confidence on Wednesday.
The Civic Democratic Party congress, which may issue Topolanek a stern report card for the loss, is planned for December.
"In the darkest nightmares I have not expected such result," said Mayor of Prague Pavel Bem, of the Civic Democratic Party.
Topolanek now hopes to mitigate the loss in the Senate election runoff next week.
Twenty Civic Democratic candidates made it to the second round, 19 of whom will face Social Democratic challengers.