File photo dated November 26, 2009 shows Andal Ampatuan Jr., suspected of masterminding the killing of 57 people in Maguindanao in Mindanao, inside the detention cell of the National Bureau of Investigations (NBI) in Manila. (AFP Photo)

MANILA, November 27, 2009 (AFP) - The alleged mastermind of an election-linked massacre of 57 people in the southern Philippines blamed Muslim rebels, in a dramatic interview from behind bars aired on local television on Friday.

Shortly after he was flown to Manila on Thursday night and thrown into a cell at the National Bureau of Investigation, Andal Ampatuan Jr. repeated comments made when he surrendered earlier in the day that he was innocent.

"I have nothing to do with it. I turned myself in and agreed to come here to show everyone that I was not in hiding and that I am innocent," Ampatuan Jr. said, gesticulating wildly as his hands were thrust through the metal bars of the bare cell.

Ampatuan accused the Moro Islamic Liberation Front (MILF), a militant organisation that has been waging a rebellion in the south of the country that has claimed more than 150,000 lives since 1978, of being behind the massacre.

"Umbrakato and the MILF are responsible," he alleged.

Ampatuan was referring to senior MILF leader Ameril Umbrakato, who is being sought by authorities for deadly raids across the southern island of Mindanao last year that left scores of civilians dead and caused half a million people to flee their homes.

The victims' relatives insist that Ampatuan ordered the killings to prevent his political rival, Esmael Mangudadatu, from running against him for the post of Maguindanao province governor in next year's elections.

Police said Ampatuan's armed bodyguards blocked a convoy of six vehicles carrying Mangudadatu's aides and relatives, as well as journalists, while en route to Shariff Aguak, the provincial capital, to register his candidacy.

The bodies of 57 victims were later found nearby, many of them buried in graves recently dug with a bulldozer.

Maguindanao is part of Mindanao island and the MILF has a strong presence there.

But the MILF spokesman, Eid Kabalu, denied Ampatuan's allegations on Friday, insisting that the 12,000-member guerrilla force had nothing to do with the murders.

"This is an attempt to condition the minds of the people," Kabalu said over ABS-CBN television.

Philippine authorities have never mentioned Umbrakato or any other MILF leader as a suspect in the massacre. They have said Ampatuan Jnr is likely going to be charged over the killings on Friday.