Iranian police warned supporters of all candidates for Iran's president about tough measures if they begin clashes, Mehr Iranian information agency reported.
"Up to now we have no problems with meetings of candidates' supporters. Police ensures full order at these meetings," general Muhsun Beigi said.
He said that there were some clashes between candidates' supporters recently.
Some clashes between candidates' supporters occurred in different towns of Iran. Several people died and injured during these clashes. Election posters were torn up. Elections centers were burned, Iranian press reported.
Presidential elections will be held in Iran on June 12. Candidates for president include current president of Iran Mahmoud Ahmadinejad, reformist National Trust Party head Mehdi Karrubi, moderate politician Mir-Hossein Mousavi and Mohsen Rezaei. Mousavi was prime-Minister of Iran in 1981-1989.