The authorities in Egypt have arrested three ex-ministers for corruption including the former Interior Minister, Habib el-Adly, judicial sources say.
Mr Adly and the ex-ministers for housing and tourism, Ahmed Maghrabi and Zuheir Garana, were detained for 15 days along with steel tycoon Ahmed Ezz.
All four, who are already banned from travelling abroad, deny any wrongdoing.
Suspicions of corruption at the top fuelled the protests which forced out President Hosni Mubarak last week.
Correspondents say the arrest of four prominent figures from the Mubarak era are an attempt by the military-led interim government to quell continuing unrest.
Charges were filed against Mr Maghrabi, Mr Garana and Mr Ezz last week, along with former Trade and Industry Minister Rachid Mohamed Rachid, who also denies misconduct.
Allegations against the four men arrested on Thursday range from money laundering to abuse of authority and squandering state wealth.
Calls for Mubarak inquiry
Mr Adly was in charge of police during the massive demonstrations against President Mubarak in Cairo and other cities and is blamed by some for the deadly use of force by riot police against protesters.
Prosecutors froze the bank accounts of Mr Adli and his family members on accusations that over 4m Egyptian pounds (£420,000; $680,000) were transferred to his personal account by the head of a contractor company, Reuters news agency reports, quoting Egyptian state TV.
Some policemen have been calling for the prosecution and even execution of the former minister.
Mr Ezz is a senior leader in Mr Mubarak's party and owner of Ezz Steel.
The company said in a statement last week that he strongly denied the accusations against him and the investigation was a personal matter that would not affect its operations.
In all, about a dozen ex-ministers and businessmen are now under investigation for corruption or abuse of authority, the Associated Press news agency reports.
Anti-corruption campaigners have been pressing prosecutors to open an investigation into the assets of Mr Mubarak and his family.
The family's wealth - put at anywhere from $1bn to $70bn - has come under growing scrutiny since Mr Mubarak resigned on 11 February after three decades in power.