The Philippines said there was a "high likelihood" a Malaysian militant suspected of being behind the 2002 Bali bombings was killed in a controversial operation in the country's south that left 44 police dead.
Sunday's offensive against "high-value targets" including Zulkifli bin Hir one of the United States's most wanted militants with a USD 5 million bounty on his head turned into a bloodbath, with President Benigno Aquino ordering a probe into the incident.
Nearly 400 highly-trained Philippine policemen took part in the operation in the remote southern farming town of Mamasapano to arrest top militants including Zulkifli, who is also known as Marwan but were ambushed by Islamist fighters.
They managed to escape but strayed into territory controlled by a different militant group, sparking another firefight.
"There is a high likelihood according to the participants that Marwan was killed in the operations, but this needs confirmation," Interior Secretary Manuel Roxas told a news conference.
While they failed to recover the body of the main target, "they were able to take pictures, and these pictures will undergo a process to determine whether it was Marwan or not."
Zulkifli, among the United States's most wanted militants, is a bombmaker for the Jemaah Islamiyah (JI) group which staged the 2002 bombings in Bali that claimed 202 lives, and other deadly attacks in southeast Asia.
A top Malaysian police official on counter-terrorism told the Malay Mail newspaper that Kuala Lumpur was still waiting for information from the Philippine authorities on Zulkifli's fate.
Zulkifli, described by the US State Department as a 48-year-old Malaysian militant and a member of JI's central command who had trained as an engineer in the United States, has long been sought by the authorities.
Declarations of his death, however, have proved premature in the past.
