Singapore said Wednesday it has offered surveillance drones and urban warfare training to Philippine troops battling Islamist fighters, to prevent the militants becoming entrenched and threatening the rest of Southeast Asia. Philippine troops have been battling to dislodge militants loyal to the Islamic State group who seized parts of the southern city of Marawi on May 23 in a bid to establish a base in the Mindanao region, which shares sea borders with Malaysia and Indonesia. IS has said it plans to establish a caliphate in Southeast Asia as it did in parts of Iraq and Syria. More than 550 people, including 413 militants and 98 government forces, have been killed in the Marawi fighting, which enters its third month this weekend.