KABUL - Two NATO soldiers were killed Wednesday following a "friendly fire" incident in Afghanistan's restive southern region, the NATO-led International Security Assistance Force (ISAF) said in a press release on Thursday.

Related readings:  2 NATO soldiers killed in shooting incident in N Afghanistan  Australian troops involved in Afghanistan battle  Three suicide bombers kill 20 in SE Afghanistan  Suicide car bombing kills 10 in E Afghanistan

However, the press release did not give more details in the so-called "friendly fire" incident, saying "An ISAF Joint Command incident assessment team is looking into the incident. A formal investigation will determine the circumstances that led to the incident,"the press release said.

Nevertheless, it did not reveal the nationalities of the victims, saying that it is ISAF policy to defer casualty identification procedures to the relevant national authorities.

Troops mainly from the United States, Britain, Canada and Australia have been stationed in the southern region within the framework of ISAF to fight Taliban militants.

More than 110 NATO soldiers, with majority of them Americans, have been killed in Afghanistan since beginning this year.

The southern Afghan provinces, regarded as "Taliban hotbed" have been the scene of increasing Taliban-led activities over the past couples of years.