"I will not apologize to the MILF," he said. "I will go further by offering to resign should it be proven that they have nothing to do with the bombings."
Duterte said he was sticking to his belief that the MILF had a hand in the blasts as the pieces of evidence gathered pointed to separatist rebels.
"The pieces of evidence that were taken by both the police and military intelligence units were strong enough to support earlier accusations involving the MILF," he said.
The mayor made his offer to resign even as President Arroyo is set to create an independent body to investigate the bombings at Davao International Airport on March 4 and the April 2 blast at Sasa wharf.
Mutinous junior military officers have accused Defense Secretary Angelo Reyes and resigned military intelligence chief Brig. Gen. Victor Corpus of ordering the bombings so the MILF could be tagged as a terrorist group.
Charges of multiple murder and multiple frustrated murder were filed against MILF chieftain Hashim Salamat and 200 rebel field commanders.
Only five of those charged are detained at the Davao City Jail.
However, the warrants of arrest for Salamat and nine other MILF officials have been lifted to pave the way for the resumption of peace talks in Kuala Lumpur next week. — Edith Regalado