A battle pitting Philippine troops against Muslim guerrillas on a remote southern island killed at least 53 people, the military said on Thursday, but analysts said the clash is unlikely to have sidelined the rebels. Soldiers killed at least 30 guerrillas during an assault on Wednesday on a base of Abu Sayyaf rebels in the interior of the southern island of Basilan, Brigadier-General Rustico Guerrero, marine commander, told reporters. "Based on this one incident alone, it would be premature to make a conclusion on the neutralization of the Abu Sayyaf," Mars Buan, an analyst at the Pacific Strategies and Assessments risk consultancy, told a UK-based news agency. "In the past, the Abu Sayyaf has suffered bigger number of casualties, but it has remained as one of the serious threats in the south."