COTABATO: Philippine President Gloria Arroyo today vowed to hunt down the perpetrators of a political massacre that left 57 people dead, as one of her allies was named the prime suspect.

Arroyo faced increasing pressure to take decisive action as more bodies were pulled out of shallow graves and relatives of the victims reported horrifying details of the killings, including that two women shot dead were pregnant.

“This is a supreme act of inhumanity that is a blight on our nation,” Arroyo said in a statement as she declared Wednesday a national day of mourning.

“The perpetrators will not escape justice. The law will hunt them until they are caught.