MANILA, Philippines?(UPDATE) Two ranking military officials have been relieved from their posts in Maguindanao to give way to "impartial and transparent investigations" on the gruesome murders Monday of at least 57 people in the province, the Philippine military said.

In a press briefing, Armed Forces of the Philippines spokesman Lieutenant Colonel Romeo Brawner, Jr. said that 6th Infantry Division Commander Major General Alfredo Cayton and 601st Infantry Brigade Commander Colonel Medardo Geslani were relieved of duty effective Friday.

The order was made following complaints of alleged "inefficiency and inaction" in handling the Maguindanao carnage, Brawner said, even as he added the two were not suspects in the mass murder.

"Definitely, they are not suspects," he told reporters.

"We will be conducting that investigation so that we will remove or erase from the minds of the people any doubt as to the investigation that we will be doing," Brawner said.

Among the complaints raised were the military's failure to respond to the victims request for security detail amid death threats being received by the camp of Buluan Vice-Mayor Esmael Mangudadatu ahead of the grisly killings, he said.

The military spokesman added that the investigation on Cayton and Geslani, to be conducted by the Inspector General at the AFP general headquarters in Manila, would soon begin.

"The relief was only effective today because we could not change the commanders in the middle of an on-going operation," Brawner said when asked about the delay in relieving the officers when officials of the Philippine National Police in the province were terminated from office days ago.

He added that the two officials were the ones who led the military in taking control of the provincial capitol of Maguindanao and the municipal halls of Shariff Aguak and Ampatuan Thursday.

Cayton will be temporarily replaced by 6th ID Assistant Division Commander Brigadier General Pompeo Limbo while Colonel Pablo Amisola, deputy brigade commander of the 601st IB will take over the post of Geslani, Brawner said.

At least 57 people, including relatives and supporters of Maguindanao gubernatorial aspirant Mangudadatu, and members of the media, were waylaid and killed in a gruesome massacre that sent shock waves across the world.

The murdered relatives and supporters of Mangudadatu, composed mostly of women, were carrying his certificate of candidacy for filing at the Commission on Elections office in Shariff Aguak when waylaid by about 100 gunmen. Members of the media were covering the event.

Mangudadatu will challenge Andal Ampatuan, Sr., patriarch of the powerful Ampatuan clan, in the Maguindanao gubernatorial race in the 2010 elections. Ampatuan?s son, Datu Unsay Mayor Andal Ampatuan, Jr., surrendered to authorities Thursday after being accused of masterminding the killings.