MANILA (REUTERS) - Philippine President Benigno Aquino approved a bungled secret mission against Islamist rebels that led to the deaths of 44 police commandos, an official report released on Friday said, piling more pressure on the beleaguered leader.

The Philippine National Police Board of Inquiry (BOI) report also found Aquino had authorised suspended police general Alan Purisima, a personal friend, to take part in the mission even as he was being investigated for corruption.

In January, police commandos sneaked into a rebel area in the south to capture Zulkifli bin Hir, alias Marwan, an al Qaeda-linked bomb-maker with a US$5 million (S$6.9 million) American bounty on his head. The commandos were ambushed by rebels and 44 were killed.

The results of the police inquiry came out days after Aquino said he was given wrong information about the secret mission, blaming the head of the Special Action Force (SAF) Getulio Napeñas for the botched mission.

The police report said Aquino, Purisima and Napenas had"kept the information to themselves and deliberately failed to inform" the chief of the Philippine National Police about the mission.

The police report was based on sworn statements from about 300 witnesses, police and military officials. Aquino, Purisima and the armed forces chief of staff were not interviewed for the report.

Earlier this week Aquino said Napenas deviated from a plan presented to him two weeks before the operation. He said he was"fooled" by the people who knew most what was happening.

Purisma's lawyer, Kristoffer James Purisima, said his client would respond to all allegations "at the proper time and before the proper forum".

Interior minister Manuel Roxas said police were still considering what charges to press in the case.

Senator Sergio Osmena III, Aquino's campaign manager for the 2010 election and now an independent legislator, said the three men cited in the report had kept Roxas and acting national police chief Leonardo Espina "in the dark ... and that's not the way to do things".

Prospero de Vera, professor of public administration at the University of the Philippines, said Aquino could face impeachment charges and there would likely be more calls for his resignation. Some lawmakers, Catholic bishops, civil society groups and activists have already called on him to step down.