Hundreds of protesters demonstrated outside the Iranian consulate in Afghanistan's western city of Herat on May 11 over the deaths of migrants who drowned after allegedly being forced into a river by Iranian border guards.
Afghan officials have said the migrants died while illegally trying to cross into neighboring Iran from Herat Province earlier in May.
Abdul Ghani Noori, the governor of the province's Gulran district, says 18 bodies have been recovered from the river so far and that some of the bodies show signs of torture and beatings.
According to Noori, a total of 55 migrants were forced into the river. He says six of them are still missing.
Iranian authorities have dismissed the claims that its security forces were involved in their deaths, saying the incident occurred within Afghan territory.
Afghan President Ashraf Ghani has ordered a probe into the drownings, forming a 10-member team to carry out the investigation.
A decree issued by Ghani orders the team to carry out a “thorough investigation into reports about the deaths of several countrymen along the Iranian border."
Human Rights Watch (HRW) on May 4 described the alleged actions of the Iranian border guards as “shocking.”
Decades of conflict, extreme poverty, and high rates of unemployment force thousands of Afghans to illegally cross the border to Iran every year.
There are currently up to 1 million registered Afghan refugees in Iran. According to the United Nations, there also are as many as 2 million undocumented Afghans in Iran.