Capt. Jose Richie Pabilonia, Southern Command information chief, said the first attack occurred last Sunday while a Marine trooper was jogging along the Jolo airstrip, just 500 meters away from the 3rd Marine Brigade headquarters.
The following day, another Marine fell from gunshots coming from a caliber .45 pistol along Arola street in downtown of Jolo at around 11:45 a.m.
Two more Marines were killed while shopping at Sincere Enterprises, also in Arola street.
Names of those killed were not immediately rleased, pending notification of their families and relatives.
"The military in Sulu theorized that the Abu Sayyaf terror squad took advantage of the military’s unilateral ceasefire in Sulu," Pabilonia said.
The six-day somo was implemented by the military in Sulu in time for the visit of Organization of Islamic Conference (OIC) officials, who were in the country to assess the implementation of the 1996 peace accord forged between the government and the Moro National Liberation Front (MNLF).
The OIC proposed during its visit to Sulu to continue the implementation of the SOMO indefinitely.
The military disclosed that there are Abu Sayyaf men who can easily merge with the MNLF faction because they have relatives within the organization.