MANILA: US forces played a “substantial” role in a botched anti-terrorism raid in the Philippines that left 44 local police commandos dead, according to a Senate report released Tuesday.

The raid, known locally as Oplan Exodus, has plunged President Benigno Aquino’s administration into crisis and jeopardized efforts to end a decades-long separatist insurgency.

“US personnel played a role in the training before, and monitoring, of the... operation,” Senator Grace Poe told reporters as she released the findings of a committee inquiry into the January 25 raid. “The committee found that the United States substantially invested in the entirety of Oplan Exodus. It provided equipment, training and intelligence.”

The raid sought to capture or kill two men on the US government’s list of “most wanted terrorists” who were living among rebels in southern Philippine farming communities.

One of the men, Malaysian national Zulkifli bin Hir who had a $5-million bounty on his head, was reported killed.

But the other, Filipino Abdul Basit Usman, escaped as rebels surrounded the police commandos and killed 44 of them.

A police inquiry earlier outlined a multitude of tactical errors that led to the slaughter of the commandos. The Senate report said Aquino must “bear responsibility” for the deaths.

But it also raised questions about the accountability of the United States, a longtime military ally of the Philippines that has so far declined to outline its role in the operation.

Three unidentified Americans were brought into the local army brigade headquarters during the operation, creating tensions with the Filipino military commander at a crucial time, the Senate report said. “One of the Americans ordered Maj. Gen. Edmundo Pangilinan to fire the artillery,” the report stated.

“However Pangilinan refused and told him: ‘Do not dictate to me what to do. I am the commander here’.”

Responding to the Senate report, a US government official told AFP: “This operation was planned and executed by Philippine authorities. We refer you to them for details of the operation.”

The United States provides military training and intelligence to the Philippines in its counter-terrorism efforts.

US forces are not allowed to engage in combat under the terms of an agreement between the allies — a deal Poe said there was no evidence to suggest had been breached.