The US military will lead the probe into the cross-border attack by NATO forces that killed 24 Pakistani soldiers, the defence department said on Monday.
The probe will "look at the full range of factors that contributed to this tragedy and it will be broad, expansive and thorough", the department's press secretary George Little said, adding that the US Central Command (Centcom) will lead the investigation.
Twenty-four Pakistani soldiers were killed November 26 when NATO fighter jets and helicopters bombed two security posts in Pakistan's Mohmand tribal region near the Afghan border. Thirteen others were injured.
The incident prompted angry protests from Islamabad.
Secretary of State Hillary Clinton and Defence Secretary Leon Panetta issued a joint statement over the weekend to offer condolences and said they are closely monitoring reports of the incident.
"The focus now is on continuing to engage with our Pakistani counterparts over time, even during difficult periods," Xinhua quoted Little as saying.
White House spokesman Jay Carney said that the administration was taking the matter "very seriously", and was "very keen" on finding out what exactly happened.
