Philippine President Benigno Aquino III warned on Monday that those who conspired with the Sulu sultan in pressing for his claim to Sabah will be penalized.
Aquino said in a speech that the clan of Sultan Jamalul Kiram III could not have acted alone when they launched their attempt to "reclaim" the Malaysian state.
"I am aware that certain personalities conspired and brought us to this situation -- one that has no quick solution. Some of these people have not yet been identified. But I assure you that these people will not succeed and that they will be brought to justice," he said in the vernacular.
Aquino said the government had launched an investigation to uncover the people who may have incited Kiram's group to go to Sabah.
He urged the Sultan and his followers to let reason prevail and prevent more bloodshed in Sabah.
In a telephone call on Saturday, Aquino said Malaysian Prime Minister Najib Razak told him that negotiation is impossible now, given the loss of life on the Malaysian side.
He said he appealed to the Malaysian side to ensure the safety of some 800,000 overseas Filipino workers (OFWs) in Malaysia.
Foreign Affairs Secretary Albert F. del Rosario left for Kuala Lumpur on Monday afternoon to meet with Malaysian Foreign Minister Anifah Aman to continue discussions on how to avert further loss of lives and to appeal to Malaysian authorities to exercise maximum tolerance in dealing with the remaining members of Kiram's group in Lahad Datu.
During the Semporna clash between Malaysian authorities and Kiram's group on Sunday, six members of the Malaysian police and 11 supporters of the Sulu sultan were killed.
Meanwhile, Aquino expressed confidence that the peace talks between the former rebel group Moro Islamic Liberation Front (MILF) and the Philippine government will not be derailed by the Sabah incident.
Malaysia is the third-party facilitator of the peace talks between the MILF and the Philippine government.
Aquino said it is in the interest of Malaysia to ensure that the peace process is concluded to ensure the stability of peace and order situation in Mindanao.