Lucknow: Chief Minister Mayawati on Sunday night sacked four ministers facing corruption charges in another clean-up act, a day after the Assembly poll schedule for Uttar Pradesh was announced by the Election Commission.

"The Governor has received recommendation of the Chief Minister to sack four ministers," Principal Secretary to Governor G B Patnaik said.

The four are Higher Education Minister Rakeshdhar Tripathi; Agriculture, Education and Research minister Rajpal Tyagi; Minister of State for Backward Welfare (Independent charge) Awdhesh Verma and Minister of State for Home Guard Hari Om.

The Chief Minister had not cited any reason for dropping the ministers in her communication to Governor B L Joshi, officials said.

The four ministers were mired in controversies as they were facing corruption charges. Tripathi is also facing a Lok Ayukta probe for alleged corruption.

The Opposition has been demanding the resignations of the four ministers for a long time.

Mayawati's action is seen as an attempt to refurbish her government's image ahead of Assembly elections after being constantly targeted by the opposition parties over corruption charges.

The BSP supremo has in the recent weeks sacked five tainted ministers on the recommendation of Lokayukta for alleged misuse of funds.

They are Ratan Lal Ahirwar, Rajesh Tripathi, Awadhpal Singh, Badshah Singh and Rangnath Mishra.

UP will go to polls spread over seven phases from February 4 to February 28.