Czech Prime Minister Petr Necas came under renewed pressure to quit on Saturday over charges that a close aide abused her powers, after the country's president - a political rival - said he believed the allegations were well-founded.
The government has been in turmoil since prosecutors charged Prime Minister Petr Necas's aide, Jana Nagyova, and seven other people as part of the biggest sweep against suspected political corruption in two decades.
A court ruled on Saturday that Nagyova must stay in custody pending an investigation into charges against her of corruption and abuse of power.
The decision is a blow to Necas, who has been facing growing pressure to quit over a scandal centered on accusations that the aide was involved in offering bribes to win loyalty from political opponents, and organizing illegal surveillance.
When asked whether he thought the center-right cabinet led by Necas should stay in office, President Milos Zeman said: "I consider the charges that have been brought to be very serious."
"After hearing from the chief of police and the supreme state attorney, I am coming to the conclusion that they are based on sufficient evidence," he said in his first remarks since a series of police raids on government offices this week.
"This is an indirect but clear answer to your question," he said at a ceremony north of the capital to commemorate Czech victims of the Nazi occupation.
In a speech to lawmakers on Friday, the prime minister dismissed the allegations and said he would stay on. He said he had done nothing dishonest and had no reason not to trust Nagyova.
The centre-left opposition has called a no-confidence vote, possibly on Tuesday, and Necas's fate now depends on whether the smaller parties in his coalition stand by him.
The leader of one junior coalition partner told Reuters on Friday her confidence in Necas was "below freezing point", but said she would take the weekend to consider the party's options.
The fact that the court on Saturday decided grant police custody of Nagyova and other defendents is a sign it believes the prosecutors at least have a credible case.
Prosecutors said Nagyova illegally asked military intelligence to follow three people and offered posts in state companies to parliamentary deputies in exchange for them abandoning a rebellion against the government.
Necas said on Friday the agreement with the political rivals was a standard political deal and should not be seen as anything criminal.
The Czech Republic emerged as a beacon of liberty after former dissident Vaclav Havel led the 1989 "Velvet Revolution" against Communist rule.
But since then, successive governments have been mired in scandals and sleaze, while law enforcement has failed to bring any high-profile convictions.
Czechs are confronted daily with evidence of what they believe is pervasive corruption, including well-connected businessmen living in plush villas, and a steady stream of media reports about kickbacks and padded government procurement deals.
The investigation into Nagyova and others was unusual because it showed a willingness by police and prosecutors to strike at well-connected people.
Around 400 officers, some clad in balaclavas to conceal their identity, raided 31 premises earlier this week, including bank safe deposit boxes, and seized at least $6 million in cash and tens of kilograms of gold.
Under Necas's watch, the government has tried to break with past habits of sweeping corruption under the carpet by appointing prosecutors with a free hand to go after sleaze.