The cease-fire between the Philippine government and the Moro Islamic Liberation Front (MILF), in effect since 2001, became jeopardized by a military clash between a force of 50 Philippine Marines and a force of an estimated 400, including MILF fighters, on Basilan island on July 10, 2007. Basilan is just west of the large Philippine southern island of Mindanao. The Marines were ambushed by a force that Philippine military (AFP) spokesmen described as consisting of MILF and Abu Sayyaf fighters. Fourteen Marines were killed, and ten were beheaded. The beheadings especially raised the level of tensions. The Marines entered an MILF area on Basilan designated under the 2001 cease-fire in search of an Italian priest who had been kidnapped, in response to intelligence reports that he was being held there. A MILF spokesman stressed that the AFP did not notify the MILF that the Marines would enter the MILF area. Under the cease-fire, a joint government-MILF Committee on Cessation of Hostilities is responsible for implementing the truce. Philippine government officials stated that the MILF knew of the Marines' rescue operations on Basilan and that the lack of official notification was not a legitimate reason for attacking the Marines. AFP officials asserted that Abu Sayyaf cadre likely did the beheadings, since beheadings are a trademark of the organization. The MILF acknowledged that its forces had participated in the attack on the Marines, but it denied that MILF cadre engaged in beheadings (beheadings, it said, violate Islamic law). The MILF was ambivalent on whether Abu Sayyaf cadre participated in the ambush. The situation escalated when the Philippine government demanded that the MILF turn over MILF cadre involved in the ambush and set a deadline of Sunday, July 22, 2007. Philippine National Security Adviser Norberto Gonzales stated that the government had submitted names to the MILF of MILF cadre involved in the ambush. The MILF declared that it would not surrender its cadre. The deadline passed, and the government and the AFP threatened to open major military operations against the MILF on Basilan and said that the AFP would hunt down the ambushers. The MILF countered that its forces on Basilan would "defend themselves to the death" and that an AFP offensive on Basilan would jeopardize Philippine government-MILF peace talks and that renewed fighting on Basilan could spread to Mindanao. The outcome of this confrontation has potential implications for the U.S. policy of providing military support to the AFP for operations against Abu Sayyaf in the southwest Philippines. The Bush Administration has sought to keep its military support role confined to operations against Abu Sayyaf. It has supported the cease-fire and peace talks between the Philippine government and the MILF. However, a breakdown of the negotiations and the cease-fire likely would confront the Bush Administration with policy decisions regarding a U.S. role in a wider war. (See the final section of this report, " Implications of U.S. Military Involvement ") President Gloria Macapagal-Arroyo voiced strong support for the United States in the aftermath of the September 11, 2001 terrorist attack. The Philippines, she said, is prepared to "go every step of the way" with the United States. President Arroyo allowed U.S. military forces to use Filipino ports and airfields to support military operations in Afghanistan. She cited morality and Philippine national interests as reasons for her pro-U.S. stand. She defined the national interest as linking a struggle against international terrorism with the struggle against terrorism within the Philippines. She supported the U.S. war against Iraq in March 2003, offering the U.S. military air space and refueling facilities and sent about 100 Filipino military personnel to Iraq for postwar assistance. However, in 2004, she withdraw the Filipino contingent from Iraq after Iraqi insurgents kidnaped a Filipino contract worker and threatened to kill him. Philippine terrorism has been multifaceted for at least three decades and has been carried out by different groups with different agendas. A significant communist insurgency, the New Peoples Army (NPA) in the 1970s and 1980s engaged in bombings, assassinations, and kidnapings. The communists today still have an estimated armed strength of over 10,000; and the Bush Administration designated the NPA as a terrorist group in August 2002. Criminal syndicates have practiced widespread kidnapings for ransom. The target of President Arroyo's policy, however, is Muslim insurgency and terrorism. This report provides an overview and policy analysis of the Abu Sayyaf terrorist group in the Philippines and the Philippine-U.S. program of military cooperation against it. It examines the origins and operations of Abu Sayyaf, the efforts of the Philippine government and military to eliminate it, the implications of a greater U.S. military role in attempts to suppress it, and the implications for dealing with the broader problem of Muslim insurgency and terrorism in the Philippines. The report will be updated periodically. Located on the big southern island of Mindanao and the Sulu island chain southwest of Mindanao, Filipino Muslims, called Moros, since the time of Spanish rule, revolted against Spanish colonizers of the Philippines from the 17 th century on, the American rulers of the early 20 th century, and Philippine governments since independence in 1946. From 1899 to 1914, the U.S. military conducted a number of campaigns to suppress Muslim insurgents in the southern Philippines—campaigns which were controversial because of heavy civilian casualties. Muslim grievances after 1946 focused on the growing settlement of Catholic Filipinos on Mindanao, which reduced the geographical area of a Muslim majority (there are about 7 million Filipino Muslims). Muslims revolted in the 1970s under a Moro National Liberation Front (MNLF), which demanded an independent Muslim state. An estimated 120,000 people were killed in the 1970s in heavy fighting between the MNLF and the Philippine armed forces (AFP). Since the late 1970s, there have been two trends in the Muslim problem. The first has been negotiations between the Philippine government and the MNLF. As a result, the MNLF abandoned its goal of an independent Muslim state. An agreement was reached in 1996 that created an autonomous Muslim region. This apparent positive trend was countered by the fragmentation of the Muslim movement. A segment of the MNLF broke away in 1978 and formed the Moro Islamic Liberation Front (MILF). The MILF demanded independence for Muslim populated regions and proclaimed that a Muslim state would be based on "Koranic principles." The MILF gained strength into the 1990s. By 1995-96, U.S. estimates placed armed MILF strength at 35,000-45,000 in seven provinces on Mindanao. The MILF had large base camps and functional governmental operations. Its operations included attacks on the AFP and planting bombs in Mindanao cities. A Bangsamoro Peoples Consultative Assembly of approximately 200,000 people was held in 1996 in MILF-held territory and called for an independent Muslim state. Stepped-up MILF military operations in 1998-99 prompted Philippine President Joseph Estrada to order an all-out military offensive against MILF base camps. The AFP captured the MILF's main base on Mindanao and damaged the MILF militarily. Since then, MILF armed strength has fallen to an estimated 13,000; but it remains the largest Muslim armed force. In 2001, Philippine government-MILF negotiations resulted in a cease-fire. The cease-fire had held, and there have been periodic peace negotiations between the government and the MILF. However, peace talks have come to a stalemate, and elements of the MILF have increased cooperation with Jeemah Islamiah, an Al Qaeda-affiliated terrorist group that emerged in Malaysia, Singapore, and Indonesia after the September 11, 2001 terrorist attack on the United States. Abubakar Janjalani, the son of a fisherman on Basilan island, formed Abu Sayyaf in 1990. Janjalani had become connected with a Muslim fundamentalist movement, Al Islamic Tabligh, in the 1980s. That organization received financial support from Saudi Arabia and Pakistan, including funds to send young Muslim men to schools in the Middle East. Janjalani studied in Saudi Arabia and Libya and became radicalized. When he returned to Basilan, he recruited two groups into Abu Sayyaf (meaning "sword bearer" in Arabic): dissidents from the MNLF and Filipinos who had fought with the Afghan mujaheddin rebels against the Soviet Union. Over the next five years, Abu Sayyaf staged ambushes, bombings, kidnapings, and executions, mainly against Filipino Christians on Basilan and the west coast of Mindanao. Its strength grew only slowly to an estimated 600 by 1995. Abu Sayyaf operations declined for four years after 1995, partly as a result of the 1996 settlement between the Philippine government and the MNLF. In 1998, AFP troops killed Abubakar Janjalani. His brother, Khadaffy, and Ghalib Andang took command. Then in 2000, Abu Sayyaf began kidnaping operations aimed at foreigners, with a principle aim of extracting ransom payments. In April 2000, Abu Sayyaf forces commanded by Andang, aboard fast speed boats, attacked a tourist resort in the Malaysian state of Sabah and kidnaped 21 foreigners, including Malaysians, Frenchmen, Germans, Finns, and South Africans. In July 2000, Abu Sayyaf seized three French journalists.