Malaysia's prime minister said Monday authorities would relocate residents of areas deemed vulnerable to foreign infiltration as they continued to try to root out Filipino Islamic invaders.
The comments by premier Najib Razak suggested concern was mounting that the armed incursion posed a long-term security threat in the eastern state of Sabah and that it may have been facilitated by a sympathetic local population.
"The primary cause of the invasion of terrorists ... is the existence of settlements considered easily exposed to the danger of infiltration by illegal immigrants and stateless persons," Najib said in announcing the relocation plan.
More than 200 armed Islamist followers of the self-styled "Sultan of Sulu" -- a new-defunct southern Philippine sultanate -- landed six weeks ago to claim Sabah for their leader, reviving a centuries-old territorial row.
The incursion and a Malaysian counter-assault in early March has left more than 60 militants dead along with 10 security personnel, according to authorities, and strained relations with Manila.
But authorities appear to have failed to catch most of the militants, with officials conceding they may have melted into the estimated 800,000 Filipinos -- many from Sulu -- living in Sabah, which has about 3 million people.
Najib said the relocations would affect areas near the eastern Sabah invasion site but could be expanded to the entire state, which for centuries has had a porous sea border with the southern Philippines.
He gave no further details.
Other officials, however, have raised more direct concerns about the allegiances of many in Sabah.
"We must... ensure that the loyalty of the Suluk community in Sabah is towards Malaysia and that there are no sympathisers," armed forces general Zulkifee Mazlan was quoted as saying Monday by The Star newspaper.
Sabah natives have grumbled for decades over an influx of Filipino Muslims, whom critics allege were given voting rights in a ploy by Malaysia's ruling party to shore up support for the Muslim-dominated federal government.
The government denies the charge, but public pressure led to an official inquiry that is still under way.
Many analysts say that at the very least border security was lax and the government faces a potential long-term security threat.
"Sabahans have been screaming and shouting for a long time yet it has fallen on deaf ears," said Sabah researcher Faisal Hazis of the University of Malaysia Sarawak.
He said there is "fear, anger and disappointment. Fear not so much of an external threat, but symphathisers," Faisal said, noting the strong roots many Sabah Filipinos retain with the Philippines.
Malaysian elections must be held by late June, with the long-ruling Barisan Nasional coalition facing a stiff challenge from a rising opposition.
Sabah was already considered an election battleground but it remains unclear whether anger over government policy would be muted by a potent wave of Malaysian nationalism that has been stirred by the conflict.
"The incursion heightens the importance of Sabah, given how the state's political situation was already somewhat fluid. I am not sure if this will translate into a significant change," independent pollster Ibrahim Suffian said.
Last week, a Malaysian court charged eight Philippine nationals with terrorism-related offences, which is punishable by death.
They were among more than 100 arrested -- apparently Malaysian residents -- on suspicion of complicity in the incursion.