Turkey has dismissed 350 police officers in the capital Ankara in the biggest shake-up since a corruption inquiry targeting government allies.
Hours later the top judiciary body said it would investigate alleged misconduct by officials overseeing the inquiry.
The sons of three cabinet ministers were among more than 50 detained in raids last month.
The government appears to be hitting back by sacking or reassigning hundreds of police, correspondents say.
Prime Minister Recep Tayyip Erdogan recently accused the police and judiciary of a "dirty plot" to undermine his administration.
He was forced to carry out a cabinet reshuffle after three of his ministers resigned following their sons' arrests.
In the latest development, the Supreme Board of Judges and Prosecutors (HSYK), which appoints senior members of the judiciary, has said it will investigate prosecutors Zekeriya Oz, Muammer Akkas, Turan Colakkadi and Istanbul's newly appointed police chief Selami Altınok, reports say.
'Political plotting'
The latest round of police dismissals was carried out under a government decree published at midnight.
Those removed from their posts include chiefs of the financial crimes, anti-smuggling and organised crime units, the private Dogan News Agency reported.
Many were reassigned to traffic or local duties.
The move comes as the government is trying to contain the political fallout from the corruption inquiry.
The mass arrests were carried out as part of an inquiry into alleged bribery involving public tenders, which included controversial building projects in Istanbul.
Many believe the arrests and subsequent police dismissals reflect a feud within Turkey's ruling AK Party - between those who back Mr Erdogan and supporters of Fethullah Gulen, an influential Islamic scholar living in self-imposed exile in the US.
Members of Mr Gulen's Hizmet movement are said to hold influential positions in institutions such as the police, the judiciary and the AK Party itself.
For years, Mr Gulen's loyalists (known as Gulenists) broadly lined up with Mr Erdogan, sharing his belief of a greater role for Islam in Turkey's secular state, says the BBC's James Reynolds in Istanbul.
Crucially, an undeclared Gulenist network in the judiciary and the police helped the government to remove the military from politics, our correspondent says.
But many in Turkey believe that the Gulenist network has now gone after the prime minister's allies because it is unhappy with the way Mr Erdogan dealt with anti-government protesters in Gezi Park.
It is also said to be angered by government plans to close a number of Hizmet-run schools - a charge the movement itself denies.
Turkey's army has said it does not want to get involved in political arguments, in response to rumours of a coup plot.
The corruption inquiry continues, with Turkish media reporting at least 27 more arrests on Tuesday linked to allegations of rigging of tenders at a port in the province of Izmir.
Officials of the state railway company are reported to be among those detained.
'Smear campaign'
The scandal has prompted anti-government protests in Turkey's main cities in recent weeks but Mr Erdogan has pledged to fight on in what is seen as the biggest challenge to his government in his 11 years in office.
He has called the corruption investigation a "smear campaign" and urged his supporters to vote for his AK Party in upcoming local elections.
Turkey's lira has fallen to a new low against the dollar.
The European Union - which Turkey hopes to join - has urged Ankara to address the corruption allegations in an "impartial manner".
This summer, Turkey will vote for a new president.
Over the past year, Mr Erdogan has positioned himself as a potential candidate but analysts say he now faces an organised opponent within the system he has dominated for a decade.
bbc.co.uk
