Afghan President Ashraf Ghani on Friday ordered a "thorough" probe into the drowning of several migrants, after Iranian border guards allegedly forced them into a river last week.
The Afghan authorities had already been investigating the incident, but Mr Ghani formed a new 10-member team to look into the deaths after 18 bodies of migrants were recovered, some of them bearing signs of torture.
Officials claim the migrants drowned in the Harirud river while illegally crossing into neighbouring Iran from western Herat province.
"President Ashraf Ghani, in a decree issued today, appointed a 10-member team to carry out a thorough investigation into reports about the deaths of several countrymen along the Iranian border," Mr Ghani's office said in a statement.
Earlier Friday, Abdul Ghani Noori, the governor of Herat's Gulran district bordering Iran, said authorities had so far recovered 18 bodies.
"Out of 55 Afghan migrants who were forced into the river, we have so far recovered 18 bodies," Mr Noori said.
He said six migrants are still missing while others survived.
The bodies "bear signs of beating and torture," Mr Noori said.
"Based on the accounts of survivors and the marks on the bodies of the victims, they were first lashed with wire cables by the Iranian border guards and then forced at gunpoint to jump into the river," he said.
The Afghan Human Rights Commission said last week the Iranian guards made the migrants cross the Harirud river and "as a result a number of them drowned".
Iranian authorities have dismissed the claims, saying the incident occurred inside Afghanistan's territory.
The United States has backed the Kabul administration's decision to investigate the incident.
"Iran's 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 earlier this week. "Those found guilty of such abuse must be held accountable."
Between 1.5 million and three million Afghan refugees live and work in Iran, most of them as wage labourers 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.
