The United States will back President Gloria Arroyo in the fight against breakaway Muslim militant groups threatening fragile peace talks in the southern Philippines, its envoy to Manila said on Monday. US ambassador Francis Ricciardone said negotiations between the Moro Islamic Liberation Front (MILF) and the government were being made difficult by many groups claiming to be legitimate separatist rebels. While the ongoing peace negotiations brokered by Malaysia to end the MILF's 28-year insurgency were welcome, Ricciardone said Washington would provide military support against those continuing to carry out attacks.He said 70 US military personnel were training troops in the southern Philippines in intelligence gathering, leading to the arrest or killing of "25 identified, known, no-doubt-about it terrorist leaders" last year. Development assistance would also continue in the mostly poverty-stricken southern Mindanao island and in Muslim areas, he said. "Our concern is not merely to get a piece of paper ... a peace accord. What we want to see is a peace (agreement) that will be durable and that will permit development to go ahead," Ricciardone told foreign correspondents.