The incident took place on June 3 after a regional police chief and several police officers tried to hold talks with hundreds of protesters who have been blocking the passage of cars on the Osh-Erkechtam highway since May 27.
Osh regional police spokesman Jenis Ashyrbaev told RFE/RL on June 4 that no one was arrested in the clashes.
Hundreds of protesters continue blocking the highway, demanding Keldibekov's release.
Keldibekov, a member of the opposition Ata-Jurt (Fatherland) party, was arrested in November and charged with abuse of office and financial misdeeds while running the State Social Fund and Tax Service.
He also served as parliament speaker between 2010 and 2011.