Eyewitnesses report a deadly crackdown on protests across Iran. Security forces allegedly opened fire on unarmed protesters. The BBC has received multiple accounts of the violence. Protests began days ago in response to worsening economic hardship. Omid, a protester in southern Iran, said forces used Kalashnikov-style rifles. He claims protesters are fighting a "brutal regime with empty hands." Hundreds are reported dead, including a referee and a student. The protests represent the biggest challenge to Iran's rulers since the 1979 revolution. The international community is watching closely. The Iranian government has yet to issue a comprehensive statement. Further escalation is feared.