The gunmen, wearing military fatigues, reportedly rounded up the men in Sitio Marangan, Barangay Muti, asked them to line up along the highway near a mosque and shot them.
Police Chief Inspector Alfredo Francisco, chief of the sub-police station in Vitali district, identified the victims as Imam Janani Ahaddin, 47, an Islamic preacher; his two brothers Mumin, 37, and Midwari, 23; and village councilor Ebong Mabanza.
"The victims were forcibly taken from their houses one by one and were massacred along the highway," Francisco said.
The suspects immediately escaped after ensuring that all the victims were dead.
"This is the handiwork of barbarism. They did not respect even the Imam and the rest of the victims that they killed helplessly," said City Councilor Mannix Dalipe, who witnessed the incident.
Dalipe immediately alerted the Department of Social Welfare in city to give assistance to the victims families.
It was not clear who was behind the attack, but it was the second incident in Barangay Muti in two weeks.
Unidentified gunmen also snatched three Muslim men praying inside a mosque on the eve of Eid al-Fitr, the Muslim feast after the month-long Ramadan, last month and their bodies were later found tied up and riddled with bullets.
Francisco said they still are trying to determine the motive of the bloody attack.
"Troops and police forces have been mobilized to track down the suspects who fled towards Ipil town in Zamboanga Sibugay province . With AFP