PMU commander Ali Hasim Huseyni confirmed the incident in conversation with Sputnik Turkiye. PMU operate jointly with the US-backed coalition to fight Islamic State in Iraq.
"The wounded have been taken to various hospitals in Iraq for treatment".
The recent airstrike is not the first time that USA forces have bombed pro-government fighters in Iraq.
"In October, an airstrike conducted by the US-led coalition in Iraq "most likely" killed around 20 pro-government Sunni tribal fighters south of Mosul".
Sayyid al-Shuhada Brigade is one of the dozens of militias that are part of Iraqi Popular Mobilization Units, which are under authority of Baghdad, but have a considerable number of groups answering to Iran's clerical leadership.
In November 2016, the Iraqi parliament gave the PMU the power of law enforcement agencies, which basically provides the militia with the same powers as the government army and police.
Speaking to Iran's Tasnim news agency, Abu Ala Welayi, Sayyid al-Shuhada's leader, accused the US and Islamic State of jointly attacking his forces, vowing to take revenge. "We call for the protection of the Iraqi-Syrian border and preventing the Americans from exploiting these borders to pass their agenda".
"The intelligence of the Hashd Shaabi command said they have no information about it (shelling on Hashd Shaabi unit), and the Joint Operations Command said that Daesh (IS group) itself used sophisticated cannons and a vehicle bomb in the attack", Abadi said at a press conference after his weekly cabinet meeting.
However, an Operation Inherent Resolve spokesperson told Sputnik that "these reports are unfounded", adding that "the coalition controlled area within the established deconfliction zone near al-Tanf remains an important area in which coalition special operations forces train and equip, advise, assist, accompany and enable Vetted Syrian Opposition (VSO) groups".