Amnesty International said Monday that the toll of protesters killed by the Iranian security forces has reached at least 143 since demonstrations broke out on November 15. The deaths have resulted almost entirely from the intentional use of firearms by the security forces - though one man was reported to have died after inhaling tear gas and another after being beaten, said the London-based human rights group. The death toll could be significantly higher, it added. “The rising death toll is an alarming indication of just how ruthless the treatment of unarmed protesters has been by the Iranian authorities,” said Philip Luther, Amnesty International’s Middle East Research and Advocacy Director. “The international community’s cautious and muted response to the unlawful killing of protesters is woefully inadequate,” he stated. He called for a strong condemnation of these killings and for describing these events as “the deadly and wholly unwarranted use of force to crush dissent.” The protests, which began after the announcement of gasoline price hikes, have been the worst anti-government unrest in Iran at least since the authorities put down the "Green Revolution" of demonstrations against election fraud in 2009. Amnesty said Monday that verified videos showed "security forces deliberately shooting unarmed protesters from a short distance". "In some cases, protesters were shot while they were running away and clearly posed no threat to the security forces. Other videos show security forces shooting towards protesters from rooftops of state buildings including a justice department building," it added.