The head of Iran's police warned protesters on Friday that all emails and text messages in the Islamic republic are monitored, the ILNA news agency reported.

Security forces in Iran clashed with opposition protesters in late December. Fifteen people died and more than 300 demonstrators were arrested. Iranian police used tear gas to disperse the crowds and were reported to have fired shots into the air. Several police officers were injured.

People were reportedly told how to participate in the illegal demonstrations through emails and text messages.

The clashes came as the country marked Ashura, a 10-day period of religious ceremonies commemorating the death of Imam Hussein, a grandson of the prophet Mohammed who was killed and beheaded in the Battle of Karbala in 680 AD by the armies of the Sunni caliph Yazid.

Ahmadi Moghaddam said police would make no concessions to protesters following the December events.

"Let those who use the services of anonymous proxy servers not think we can't monitor their activity. We just went easy on them before today," he said.

Moghaddam pledged harsh punishment for those who organize illegal protests that turn into large-scale public disorder.

MOSCOW, January 15 (RIA Novosti)