Hundreds of people protested outside the Iranian consulate in western Afghanistan Monday over the deaths of several migrants who were forced into a river by Iranian border guards and drowned. Afghan officials claim the migrants died while they were illegally crossing into neighboring Iran from Herat province earlier this month. Eighteen bodies, some bearing signs of torture and beatings, have been recovered from the Harirud river so far, Gulran district governor Abdul Ghani Noori told AFP last week. Noori said 55 migrants were forced into the river. A government-backed probe is under way, but Iranian authorities have dismissed the claims, saying the incident occurred inside Afghanistans territory. "Death to (President Hassan) Rouhani, Death to (Ali) Khamenei," chanted protesters outside the consulate in Herats provincial capital of the same name. "These Afghan laborers, who had gone for a morsel of food, were viciously and brutally killed by the Iranians and thrown into the river," Nafisa Danish, an activist at the protest, told AFP. "Where are the human rights? This Iranian massacre should be condemned." Another protester Suraya Ahmadi called on Afghan, UN and Iranian authorities to probe the case. "We staged this protest to condemn the killing of our people who went to Iran to support their families," Ahmadi said. Forensic evidence and survivor accounts show the Iranian border guards first flogged the victims with wire cables then forced them at gunpoint to jump into the river, Noori said last week. The Afghan Human Rights Commission has said the Iranian guards made the migrants cross the Harirud river and "as a result a number of them drowned". The United States, which frequently trades threats with Iran and has imposed strict sanctions on the country, has backed the Kabul administrations decision to investigate the incident. "Irans cruel treatment and abuse of Afghan migrants alleged in these reports is horrifying," US Acting Assistant Secretary for South Asia Alice Wells said on Twitter last week. Between 1.5 million and three million Afghan refugees live and work in Iran, most of them as wage laborers on construction projects. Tens of thousands returned to Afghanistan after the coronavirus outbreak, but as restrictions ease in badly hit Iran, many are again seeking work there.