(UPDATE) Police unveil US involvement in clash

MANILA, Philippine (Xinhua) - A report released today by the police showed that six American nationals were involved in the police operation in January that left 44 policemen killed.

According to the Philippine National Police (PNP) Board of Inquiry, the six Americans were spotted in a Tactical Command Post along with several PNP officials in Mamasapano in southern Philippine province of Maguindanao.

The Americans are said to have provided "real-time information" in aid of the operation launched on Jan. 25 targeting Islamist terrorist and bomb technicians Zulkifli bin Hir, alias "Marwan", and Abdul Basit Usman, said PNP.

Marwan was killed in the operation while Usman escaped and remains at large.

The United States' Federal Bureau of Investigation had a $5 million reward for the capture of Marwan, under their Rewards For Justice Program. Usman had a $1 million reward for his capture from the FBI, and a P6.4 million ($145,454) reward from the Philippine government.

An index finger was cut from the slain Marwan's body and sent to the United States' FBI forensic laboratory for DNA analysis to confirm his identity.

During the operation, the six Americans piloted helicopters in the medical evacuation of wounded PNP personnel.

There have also been reports of sightings of US Surveillance Drones flying in the area of Mamasapano where these events took place.

The United States has been involved in counter-terrorism operations in the Philippines for over a decade.