The Department of Justice is seeking the transfer of the trial against suspects in the Mamasapano encounter in order to protect a key witness to the bloodbath that left 44 elite police troopers dead.

Justice Secretary Vitaliano Aguirre II said he directed state prosecutors to file a motion for the transfer of trial venue from Cotabato to Manila because security concerns have made it "practically impossible" for the DOJ witness to testify in Mindanao.

"Mayroon po tayong star witness na nagturo ng karamihan diyan sa 100 na accused na hindi makaka-statement kapag doon sa Mindanao," Aguirre told radio DZMM.

"Iyan po ay talagang iniingatan. Talagang practically impossible for him to testify in Cotabato, lalong-lalo na sa Maguindanao."

(We have a star witness who identified majority of the 100 accused and who cannot give his statement if the trial will be held in Mindanao. We are taking extreme care of our witness. It is practically impossible for him to testify in Cotabato, especially in Maguindanao.)

Respondents to the complex crime of direct assault with murder include commanders and members of the Moro Islamic Liberation Front (MILF), Bangsamoro Islamic Freedom Fighters (BIFF), and private armed groups -- all of which have strongholds in the south.

Aguirre said the court has not yet responded to their motion for the trial venue's transfer.

"I'm just speculating na maaaring may pressure din sa judge kaya up to now ay hindi pa rin naaaksyunan," he remarked.

(I'm just speculating that there may be pressure on the judge and that's why the motion remains pending.)

The country marked Wednesday the second anniversary of the Mamasapano tragedy, which saw over 60 individuals, including 44 SAF troopers, killed in an anti-terror operation.

A joint Senate committee report earlier said former President Benigno Aquino III was ''ultimately responsible'' for the botched mission to neutralize Malaysian bomb maker Zulkifli bin Hir alias Marwan and his Filipino cohort Basit Usman.

• READ: Duterte recalls day with Aquino during Mamasapano incident

President Duterte on Tuesday said he will create a commission to probe who should be held accountable for the massacre.