Haalvsh, which monitors events in the southeastern province, said around 120 Afghan nationals, including women, children and elderly people, came under fire on September 8 in the border district of Golshan.
The group said Iranian forces used both heavy and light weapons, including a DShK heavy machine gun, without issuing a warning.
According to Haalvsh, the bodies of five of the dead were left at the scene, and one of the wounded lost a leg after being hit by heavy gunfire. It also released the names of those hospitalized in Saravan, adding that the condition of three was critical.
The rights group said about 40 others were detained by border forces.
The US-based Human Rights Activists News Agency (HRANA) described the shooting as “a violation of fundamental human rights,” citing the direct fire on unarmed migrants, including women and children, and the use of heavy weapons. HRANA said the failure to provide timely medical treatment and the collective arrests also breached international law.