"The majority of those suspended are ordinary-level party workers," a BSO office bearer said in a news agency, on conditon of anonymity.
"The activists who have been shown the door include Mukhtar Ansari and Afzal Ansari. Both of them have already been expelled from the party," he added.
On Apr 16, Mayawati had expelled the Ansari brothers-Afzal and Mukhtar for their alleged role in criminal activities.
The duo are in prison for their involvement in the murder of Bharatiya Janata Party (BJP) legislator Krishnanand Rai, who was shot death in a broad daylight ambush near Allahabad in November 2005.
The move to expel around 500 party activists was made by the BSP chief on late Saturday, May 1, evening during a meeting with BSP office bearers.
However, the party's cleaning drive as been termed as "an eyewash to win the confidence of the people".
"The point to be noted is that the action has been taken against ordinary workers. She (Mayawati) just cannot afford to take action against MLAs or MPs as it would disintegrate her party," state BJP spokesperson H N Dixit told reporters.
In line with Dixit's statement, Congress' state spokesperson Akhilesh Pratap Singh said that the move was just a drama.
"It's just drama...Mayawati just cannot eliminate senior members, ministers and MLAs facing criminal charges because she knows very well that the move will break the party and she would not be able to rule the state."