A joint U.S.- Afghan military operation has freed at least 40 Afghan soldiers and police held captive in a Taliban prison in the southern Helmand province, officials said Friday.

Ground troops from the Afghan Special Security Forces and the U.S. Special Mission Wing carried out a helicopter assault on the prison in the Nawzad district, the Associated Press reported.

However, there is some conflicting information about the total number of prisoners that were freed. Afghan military spokesman Gen Dawlat Waziri said that over 60 prisoners were freed in the operation, while the U.S.-issued statement reports that only 40 were freed.

The cause for the discrepancy is still unknown. In addition, how and when the prisoners were taken captured is still unknown.

"The liberated prisoners were released to the Ministry of Defense authorities to receive medical care. The information on their initial capture is not known," the statement said, according to NBC News. 

The initial objective of the operation was to arrest a Taliban commander in the facility. Regardless of the objective, the raid marks a rare success for Afghan security forces who have been struggling to repel insurgents that continue to expand northward.

The insurgents captured Kunduz city in the northern Kunduz province for three days in September, and have stepped up attacks on government and foreign targets since launching their annual summer offensive in late April, according to AFP.

The raid also comes as speculation swirls over whether Taliban leader Mullah Akhtar Mansour was critically wounded in a firefight between insurgent commanders near the Pakistani city of Quetta. The Islamist group has vehemently rejected the claims, but an Afghan government spokesman claimed on Twitter that Mansour died during the fight.