ZAMBOANGA CITY: A few hundred supporters of political allies of Philippine President Gloria Arroyo who are suspected to be involved in the brutal slaying of 57 people held a rally Sunday in Maguindanao province as a show of force to the embattled Muslim clan.

Radio reports said the supporters were demanding the release of Datu Unsay Mayor Andal Ampatuan Jr., who was arrested on Thursday in connection with the brutal killings of more than two dozen journalists and political campaigners of a rival faction in Maguindanao province.

The mayor denied involvement in the massacre and blamed it to the Moro Islamic Liberation Front rebels, an accusation flatly rejected by the authorities and the MILF.

Reports suggested that many of those who joined the rally were paid as much as 1,000 Philippine peso each, but this could not be independently confirmed.

Justice Secretary Agnes Devanadera said they are also investigating the mayor’s father Andal Ampatuan Sr., the governor of Maguindanao, and his elder brother, Zaldy Ampatuan, the governor of the Muslim autonomous region, and five more clan members in connection with the Nov. 23 killings.

The Ampatuans are key political allies of Arroyo in the southern Philippines. Of the 57 people brutally murdered, at least 29 were journalists, according to the international media watchdog Reporters Without Borders.

The journalists were traveling in a convoy with the wife and relatives and supporters of Buluan town Vice Mayor Esmael Mangudadatu in Maguindanao’s Shariff Aguak town when they were held by more than 100 gunmen from a rival faction and herded to a remote hillside where they were executed.

Mangudadatu and the young Ampatuan are both running for governor in next year’s polls.

The Philippine military on Friday also relieved Maj. Gen. Alfredo Cayton, chief of the 6th Infantry Division, and Col. Medardo Geslani, commander of the 601st Infantry Brigade, for failing to prevent the gruesome killings. Both are under investigations in Manila.