Manila ( CNN ) Forty-three elite police commandos were killed by Muslim insurgents in the southern Philippines Sunday , when they were ambushed while pursuing `` high value '' terrorist bomb makers . The commandos , members of the elite Special Action Force ( SAF ) unit of the Philippine National Police , were killed in a firefight that raged for 12 hours in Mamasapano town , Maguindanao Province , said police deputy director general Leonardo Espina . Eleven police commandos had also been wounded in the firefight , he told a press conference in Cotabato City Monday . Members of both the Moro Islamic Liberation Front ( MILF ) , with whom the government has signed a peace agreement , and the Bangsamoro Islamic Freedom Fighters ( BIFF ) , with whom it has not , were involved in the firefight , officials and rebel groups said . Grisly footage purporting to be of the aftermath of the battle was circulated online , showing uniformed bodies strewn in a rice field . `` This is the single largest loss of life in recent memory , '' Secretary of the Department of Interior and Local Government Mar Roxas told the press conference , calling for a moment of silence from assembled reporters . `` These SAF operatives are fallen heroes . They were just doing their job ... That is why we salute them . '' Roxas said that 392 SAF commandos been engaged to hunt Malaysian bomb-maker and Jemaah Islamiyah leader Zulkifli bin Hir , known as Marwan , and Filipino bomb maker Abdul Basit Usman . The FBI says that Marwan , who is suspected of having conducted bomb making training for Abu Sayyaf and has a $ 5 million State Department bounty for information leading to his arrest , is believed to have been hiding in the country 's south since 2003 . The U.S. government is also offering a reward of up to $ 1 million for information leading to Usman 's arrest . Roxas said the commandos were retreating from the assault on their targets when they came under fire from members of the BIFF . In maneuvering away from the BIFF assault , they strayed into territory controlled by the MILF several kilometers away , and a `` misencounter '' ensued . The government had not been seeking to sabotage the peace agreement with the MILF by carrying out the operation without their knowledge , he said . `` We are hopeful and confident that this will not derail the peace talks , '' he said . `` This was not directed against MILF , but this is directed against a very , very specific high-profile terrorist bomber who was in the area . '' Espina said that it was `` most highly likely '' that Marwan has been killed in the SAF assault , and DNA testing was being carried out to confirm this . But initial reports suggested that Usman had fled . A board of inquiry would conduct an investigation into the operation , including looking into the apparent lack of coordination with MILF forces in the area , said Espina . Mohagher Iqbal , chief negotiator for the MILF , said in an interview with Philippine radio station DZRH that a lack of coordination between the MILF ceasefire committee and the government was to blame for the outbreak of violence . It was a standard operating procedure that one side should notify the other before they began an operation , he said , describing the incident as self defense . While the area where the fighting occurred was mostly under MILF control , he said , BIFF , which was also involved in the firefight , was a mobile group , moving throughout the region . `` Chances are they were just there when it happened , '' he said . He said his group was doing everything it could to ease tensions over the fighting , and that the incident would not have an effect on the ongoing peace process . The Philippines signed an agreement with the MILF , the largest rebel group in the south , in March last year . The deal offered greater autonomy , economic and political power in return for the rebels surrendering their weapons and ending a decades-long insurgency . But hardline rebel groups opposed to the peace process , such as the BIFF , remain active . Lieutenant Colonel Harold Cabunoc , public affairs office chief for the Armed Forces of the Philippines , appealed to the hardline BIFF group Monday to return any personnel under their control . `` We are also calling on our brothers in the Bangsamoro Islamic Freedom Fighters that if indeed they are still holding some of the PNP ( Philippine National Police ) personnel , they must respect their rights and they must be returned to their mother units and ultimately to their family members , '' he told reporters . Miriam Coronel-Ferrer , chair of the government panel responsible for overseeing the peace process with Muslim insurgents , said in a statement Monday that the violence highlighted the `` challenges that confound the peace process . '' But the outbreak only strengthened the resolve of the peace panel to implement the `` Bangsamoro Basic Law '' -- the bill , currently being heard by politicians , that seeks to implement the peace deal between the government and the MILF . Hearings of the bill were suspended Monday following the violence . `` With better cooperation , we will be able to prevent these kinds of incidents , '' she said .
43 police commandos are killed in a firefight with Muslim rebels in southern Philippines . Police were hunting bomb makers allegedly connected to Islamist terror groups . The death toll is the highest for Philippine forces since President Rodrigo Duterte took office last year.