The corruption inquiry has ensnared sons of government ministers, municipal workers and businessmen, including a powerful construction tycoon. The moves on Friday — by Mr. Erdogan’s government and his Justice and Development Party to contain the investigation, and by prosecutors and the police to advance it — came as Turkey braced for a cabinet reshuffle that some opposition lawmakers demanded and that the local news media suggested was imminent.

The investigation began Tuesday morning with a series of raids on the offices of businessmen and others close to the governing party. Mr. Erdogan’s government says it is a plot against its rule by a “criminal gang” within the state and has swiftly responded by purging senior police officials who have led the investigation.

On Thursday, the Istanbul police chief, Huseyin Capkin, was fired, and at least 34 officers have been dismissed or transferred by the Interior Ministry this week. In addition to the 14 police officials who took part in the dawn raids and were dismissed on Friday, the deputy chief of the Financial Investigation Commission was discharged.

Mr. Erdogan called the investigation a foreign-backed plot to topple his government ahead of a crucial election year and said those behind it were trying to form “a state within a state,” an indirect reference to Mr. Gulen and his network of followers who have positions in the government.