MANILA - The legal opinion Justice Secretary Leila De Lima is putting together on the Sultanate of Sulu's Sabah claim will be comprehensive and, aside from zeroing on the legal issues, may also tackle the issue on who are the rightful heirs to the Sultanate.

Speaking to reporters at the Department of Foreign Affairs following a meeting in Malacanang, de Lima said government was still confirming reports about the reported clash between the Sultanate's "royal army" holed up in the village of Lahad Datu and Malaysian security forces.

"Definitely, the government, through the DFA (Dept of Foreign Affairs), will have the answer/confirmation within the day. Yun (clash, violence) nga talaga, iniiwasan natin kaya nga nag-apila tayo sa kanila na umuwi na. The more natatagalan, nagiging volatile ang situation," she said.

De Lima said that as of yesterday, her understanding was that Malaysia was granting the Philippine government's request for an extension of the deadline for the "royal army" to vacate Lahad Datu.

According to the camp of Sulu Sultan Jamalul Kiram III, 10 of their Tausug fighters have died, and 4 injured in today's firefight. The claim could not be independently confirmed, as of posting.

The justice department was directed by President Aquino to submit a memorandum on the Sabah claim. De Lima said she will need time to make the report.

"It will include the legal aspect, the basis of the Sabah claim, ano naging developments sa claim na yan, ano ginawa ng previous administrations and bakit naging dormant, what's the status of the claim -- if weak or strong," she said.

The suggestion of bringing the dispute before the International Court of Justice (ICJ) will also be studied, De Lima said.