Witness says Iranian police using tear gas to disperse crowds at Rafsanjani sermon

TEHRAN, Iran (CNN) - Iranian police have used tear gas to disperse crowds attending cleric Ali Akbar Hashemi Rafsanjani's Friday sermon at Tehran University, a witness told CNN.

A large crowd has gathered to hear the former president's highly anticipated remarks. Some are wearing green wristbands, the color of opposition leader Mir Hossein Moussavi's candidacy.