MANILA- Former president Benigno "Noynoy" Aquino III said he was surprised by the charges filed by the Ombudsman over the botched 2015 anti-terror raid in Maguindanao province that left 44 elite policemen dead.

Aquino said he was "definitely" surprised with the decision of the Ombudsman to charge him with usurpation of authority and violation of the anti-graft and corrupt practices act.

"Definitely [surprised]. But I want to make sure…sabi ko, was I ever charged for this offense or was there a complaint ever filed? And my lawyers responded: There was no such complaint. So to get a decision on something you were not aware you were complaint about, and you never had the opportunity to respond to really was a surprise," he said in an interview with The Philippine Star Monday.

Ombudsman Conchita Carpio-Morales last Friday ordered Aquino charged along with Aquino's former national police chief, retired Director General Alan Purisima and the former chief of the police Special Action Force, retired Director Getulio Napeñas.

Aquino will appeal the indictment, his former deputy spokesperson Abigail Valte said.

The former president said he was not given the chance to respond or refute the allegations made against him since there was no complaint as to usurpation of authority and violation of the anti-graft and corrupt practices act.

"There was no complaint. And the complaint would normally be the form of an affidavit of complaint to which you are asked to submit your counter affidavit and refute the facts presented by the complaint. But since I wasn’t complained about with regards to usurpation, we never had the chance to rebut or refute any of the allegations," he said.

"One of the things I asked my lawyers were just to recapitulate what were the charges that we were supposed to be addressing and that was reckless imprudence resulting to homicide of which the Ombudsman said there’s no probable cause," he added.

It was Aquino who appointed Morales, a former Supreme Court magistrate, to the anti-graft post in 2011.

Morales swore in Aquino in 2010, when the latter shunned tradition and opted to officially assume his post before an Associate Justice, refusing to take his oath before then Chief Justice Renato Corona.

Aquino had opposed his late appointment by former President Gloria Arroyo shortly before the end of her term.

President Rodrigo Duterte, on Monday meanwhile defended his predecessor from the Ombudsman's finding of criminal negligence against Aquino.

Duterte said it was a "silly" decision to charge Aquino with usurpation of authority for consulting Purisima about a mission to neutralize Malaysian bomb maker Zulkifli bin Hir alias Marwan.

Duterte said while the criminal charges are faulty, the blame would obviously be pinned on Aquino since he was the commander-in-chief at the time.