PARIS — The future of the Czech government was called into doubt Friday after law enforcement officials said they had charged a senior aide of Prime Minister Petr Necas with abuse of office and bribery.

The charges, coming a day after extensive nationwide raids on government and company offices by a unit investigating organized crime, appeared to be part of the most sweeping anticorruption operation since the Czechs overthrew Communism in the Velvet Revolution of 1989.

Mr. Necas remained defiant on Friday, telling Parliament that he would not resign and had done nothing wrong. But the online version of Mlada fronta DNES, a leading newspaper, reported that the request for a no-confidence vote had already been submitted by the opposition Social Democrats and could take place as early as next week.

“The Social Democrats expect the speedy resignation of Prime Minster Petr Necas and the entire government,” a party official, Jeronym Tejc, was quoted as saying by Reuters. “If that does not happen, the Social Democrats will initiate a vote of no confidence.”