Gunmen ambushed and killed six Malaysian policemen as fears mounted that armed intruders from the southern Philippines had slipped into at least three coastal districts on Borneo island, officials said Sunday.
Six of the attackers were also fatally shot Saturday night, while another was beaten to death by angry villagers, escalating tensions in eastern Sabah state, where Malaysia's biggest security crisis in recent years began after about 200 members of a Philippine Muslim royal clan occupied a village last month to claim the territory as their own.
Security forces clashed with the clan members in the coastal area of Lahad Datu on Friday, leaving 12 Filipinos and two Malaysian police commandos dead.
The remaining clan members have refused to budge, while concerns have grown that other groups from the Philippines' restive southern provinces might enter Sabah, which shares a long and porous sea border with the Philippines that's difficult to patrol. The Malaysian and Philippine navies have strengthened their presence in waters near their border, according to Filipino officials.
A police team was attacked late Saturday while inspecting a settlement in Semporna town, more than 150 kilometers (90 miles) from Lahad Datu, said national police chief Ismail Omar.
Six of the assailants were fatally shot by police at the settlement and another was beaten to death by villagers whom he apparently tried to take captive while armed with a rifle, said Sabah police chief Hamza Taib.
Police said they were also investigating sightings of armed foreigners in military-style clothing in a third Sabah seaside district nearby.
It was not clear whether the groups in the three areas had links to each other.
Malaysian Prime Minister Najib Razak said Sunday that army reinforcements have been sent to Sabah, adding that he was confident about their ability to control the situation.
The Filipinos who landed in Lahad Datu on Feb. 9 say ownership documents from the late 1800s prove the territory is theirs. They have rejected repeated calls from both the Malaysian and Philippine governments to leave Sabah, a short boat ride from the southern Philippines.
Police dropped leaflets by helicopter over the occupied village Saturday telling the Filipinos to give up, while the navy bolstered patrols in waters between Malaysia and the Philippines.
Three of the intruders tried to escape late Saturday and were caught, Ismail said, without elaborating.
The standoff has raised territorial issues in Sabah and the southern Philippines to an immediate national security concern for both countries.
Malaysia's government, which faces a national election within less than four months, is under pressure to stop cross-border incursions that have resulted in occasional kidnappings by Filipino gunmen in past years.
It could affect how authorities deal with tens of thousands of Filipino migrants living in Sabah, including many undocumented workers, if they become perceived as threats to public safety. Any plan to deport them on a large scale, as Malaysia has sometimes attempted, would be a delicate diplomatic issue.
The crisis could also complicate peace talks brokered by Malaysia between Manila and the Moro Islamic Liberation Front, the main Muslim rebel group in the southern Philippines.
Philippine diplomats in Malaysia deployed a team that includes a consul general and a police attache to Lahad Datu and sought access from Malaysian police for the group to help provide assistance to Filipinos who have been wounded and displaced by the violence. They urged jittery Filipino residents in Sabah to stay calm and avoid any action that might complicate the problem.
The Lahad Datu group is led by a brother of Sultan Jamalul Kiram III of the southern Philippine province of Sulu.
In Manila, Jamalul Kiram III told reporters that he was worried the violence in Sabah might spread because many Filipinos, especially followers of his sultanate in the southern Philippine, are upset by the killing of their compatriots in Lahad Datu.
His daughter, Jacel, who is a sultanate princess, called on Filipinos to stay calm but stressed the sultanate would never back down from its struggle to reclaim Sabah.
"This concerns honor above life," she told reporters. "We will not retreat just like that, because we're fighting for something and our struggle is our right and the truth."
Some opposition politicians in the Philippines have used the crisis to snipe at the government of President Benigno Aquino III, prompting an official to appeal to groups seeking to exploit the issue to stay away from "an already tense situation."
"What we would like to remind anyone who is tempted to get involved in this issue for political reasons is that there are actual lives at stake here," presidential spokesman Ricky Carandang said. "It's not just about politics."
Associated Press writer Jim Gomez in Manila, Philippines, contributed to this report.