Since August, about 6,000 Army troops and Marines have been searching for Indonesians Umar Patek and Dulmatin, suspected members of the al-Qaeda-linked Jemaah Islamiyah (JI) network who fled to Mindanao after allegedly plotting the 2002 Bali bombings that killed 202 people.
The United States has offered a $10-million reward for the capture of Dulmatin and $1 million for Patek.
The two are believed to be hiding in the jungles of Sulu with leaders of the extremist Abu Sayyaf group, notorious for kidnappings, beheadings and terror attacks.
"The arrival of these forces will significantly augment Marine units ... which are battling the members of the Abu Sayyaf and their JI cohorts in the coastal and hinterland areas," said Marine spokesman Lt. Col. Ariel Caculitan.
He said the reinforcements sent last Sunday included a battalion of 500 soldiers and 160 Marines.
Although the massive operations have not resulted in the arrests of key leaders, they have kept the militants on the run and prevented them from plotting new attacks at a time when the country is preparing to host the annual Association of Southeast Asian Nations (ASEAN) Summit this weekend, Caculitan earlier said. — James Mananghaya, AP