MTC Branch 4 Judge George Omelio issued the subpoenas in connection with the tumult and public disturbance charges filed against Manuel Borja, 24, the alleged leader of the pro-Estrada group.
Omelio directed the two senators to attend the hearing on Aug. 30-31. He acted on the petition of public prosecutor Oscar Te.
Borja, who is out on P16,000 bail bond, was reportedly caught holding a "Erap Pa Rin" streamer when police rounded up the Estrada supporters.
About 100 Estrada loyalists managed to penetrate the PPC campaign rally and caused a commotion when they heckled the administration’s candidates, calling Flavier "dwarf" and Drilon "pig."
The Estrada followers hurled plastic bottles of mineral water and empty bottles of an energy drink on stage, hitting some of the candidates, including Drilon.