MANILA: The patriarch of a powerful family, Maguindanao Governor Andal Ampatuan Sr, is one of eight members of his clan indicted by prosecutors probing a sensational massacre of 57 people in the southern Philippines.

Many members of the clan have retreated into their clan home and have petitioned the Supreme Court to block arrest.

Ampatuan Sr's son, Mayor Andal Ampatuan Jr, is already in jail on charges of masterminding the election-related killings.

Another of Ampatuan Sr's sons, Governor Zaldy Ampatuan of the Autonomous Region of Muslim Mindanao, has also been asked by Interior Secretary Ronaldo Puno to answer within five days allegations that he failed "to protect the civil, human and political rights" of the victims.

Meanwhile, the elder Ampatuan, the "godfather" of the feared clan with formerly close ties to President Gloria Arroyo, was charged by the National Bureau of Investigation with multiple murder, damage to property and robbery.

The charge sheet names seven other Ampatuans, including Mr Zaldy Ampatuan. The "godfather" was included in the indictment after a backhoe owned by the provincial government was recovered from the crime scene. It was used to bury 35 of the victims in mass graves.

In response, Ampatuan Sr and his kin have applied to the Supreme Court to stop law enforcement authorities from arresting any member of the clan without warrants issued by the court.

More Ampatuans may be charged.

Yesterday, the Philippine army sent hundreds of extra troops to guard the Ampatuan home. The extra battalion of 400 soldiers brings to more than 3,000 the number now guarding the residence.

Supporters of the clan, which has ruled strife-torn Maguindanao for a decade and has its own private army, were being barred from entering the home in the provincial capital of Sharrif Aguak, military spokesman Colonel Romeo Brawner said.

Col Brawner said the extra military presence was needed to prevent further explosions of violence, including possible revenge attacks from the Mangudadatu clan, which was the target of the massacre and which is also known to have armed supporters.

The move is also meant to support the national police if arrest warrants are issued.