The attack near Bagram Airfield, the largest US military facility in the country, is the latest in a string of brazen Taliban operations, including a recent assault on the Spanish Embassy in Kabul and an attack on the Kandahar airbase.
The fighting near the city of Lashkar Gah comes three weeks after the Taliban scored a major victory by briefly capturing the northern city of Kunduz.
If confirmed, the alleged friendly fire incident in Afghanistan's opium-rich Helmand province would be the deadliest the country has seen in years.
The International Crisis Group’s latest report about the Afghan Local Police program says in many cases it has empowered local militias who are not accountable to the Afghan government.
Eleven security forces were killed in a Taliban attack in Helmand late on Wednesday. Army and police deaths have soared since the US and NATO ended their combat mission in Afghanistan last year.
Security officials in Afghanistan said that armed insurgents killed three police officers and four civilians in the attack, which took place in the capital of Helmand Province.
Mullah Abdul Rauf, who spent time in Guantanamo Bay and was a former Taliban commander, was now believed to be actively recruiting for the Islamic State in Helmand province, southern Afghanistan.
The incident occurred just hours before Afghan forces took control of the country's security at the conclusion of the joint US-NATO mission.
As foreign forces withdraw from Afghanistan, violence is increasing. VICE News correspondent Ben Anderson visited an NGO-operated hospital in Lashkar Gah to speak with the medical staff as they attempt to manage the ever-growing influx of patients.