A firefight between Malaysian police and followers of the Sultan of Sulu erupted Friday morning, reports said.
The Filipino group claimed they were attacked first.
Malaysian security forces fired at the Sulu sultan's group early Friday, Raja Muda Agbimuddin Kiram, the leader of the Pinoy group in Sabah, said in a radio interview.
"Biglang pumasok sa amin (They came in all of a sudden), we had to defend ourselves," Raja told dzBB.
The Sulu sultan's followers have staked out in Sabah, which they claim to be their homeland, since Feb. 9.
Princess Jesel Kiram, the daughter of Sulu Sultan, meanwhile, said that casualites have been reported from their camp.
"May patay na po sa panig ng grupo namin. Obvious ang kapabayaan at panggigipit ng gubyerno sa Sultanate of Sulu (Some have been killed in our group.
The government's negligence for the Sultanate of Sulu is evident)," she said in a separate interview with DZRH.
But Raja Kiram said that they will not back out. "Tuloy pa rin (We will keep on fighting)," he said.
The Sultanate of Sulu spokesperson Abraham Idjirani, for his part, appealed for a peaceful resolution of the standoff.
"We are hoping na sana matigil na (We are hoping that the firefight will stop), we want a peaceful resolution," he said.
Reports have also floated the possibility that Raja Kiram has been arrested by Malaysian forces.
But Sulu Sultan Jamalul Kiram III said he does not believe Raja Kiram's reported arrest, even as he noted that he is not directly receiving reports from the ground.
"Hindi ako naniniwala. Mahuhuli lang yan kapag patay na (I don't believe it. He will only be caught if he's dead), he said in an interview with DZRH.
The Foreign Affairs department and Palace officials, meanwhile, said they are still verifying reports on the firefight.
Interior and Local Government Secretary Manuel Roxas II noted that warning shots have earlier been reported from the Malaysia camp which said some members of the Pinoy group violated their security cordon.
He said in a radio interview with DZMM, however, that this is separate from the unconfirmed reports on exchange of gunshots between the two parties.
The Cabinet official also hit the Sultanate of Sulu for asserting their claim on Sabah despite appeals for them to step back.
President Benigno Aquino III on Tuesday ordered Kiram to ask his followers to pull back. "Mercy ships" have also been sent to Sabah to convince members of the the group, some of them armed, to return home.
"Ang priority ng pamahalaan, ang priority ng pangulo ay ang buhay at kaligtasan ng mga mamamayan (The government's and the president's priority is the life and safety of the citizens)," Roxas said.
This, as he noted that the Malaysia government's deadline for the Sultanate to pull its forces out of Sabah has lapsed.
"[A]ng ibig sabihin noon ay anytime pwede na silang hamakbang (This means that they can make a move anytime)," Roxas said.