Iran’s police chief on Friday warned opposition supporters not to use cell phones and e-mail messages to organize protest rallies against the government, saying those who do so will be prosecuted and punished.

Gen. Ismail Ahmadi Moghaddam said spreading the word of the opposition through Internet or cell phone SMS is a crime that deserves severe punishment and that the authorities would continue monitoring those systems.

The remarks are the latest reflecting the government’s frustration at various imaginative ways the opposition has sought to rally supporters following the disputed June presidential election.

A harsh government crackdown has left the opposition with little means to make its voice heard. Almost all pro-reform newspapers have been closed since the June 12 vote in which President Mahmoud Ahmadinejad was declared the winner. Those still in circulation have been openly threatened against publishing opposition statements. Iranian state media, controlled by hard-liners, regularly ignore the opposition.