Lahad Datu - Five Malaysian policemen and two gunmen died in a fresh clash on Borneo as fears mounted that violence linked to a deadly stand-off with Filipino intruders had spread to other areas, police said on Sunday.
The shoot-out late on Saturday in the town of Semporna followed a fire fight the day before between Filipino followers of a self-proclaimed sultan and Malaysian security forces that left 12 intruders dead along with two police officers.
The new clash in Semporna, 300km from the site of the three-week stand-off, occurred when police were "ambushed" by gunmen during a security sweep, Malaysia's national police chief Ismail Omar told reporters.
An estimated 100-300 Filipinos have been surrounded in a farming village by a Malaysian police and military cordon since landing by boat from the nearby Philippines on February 12 to insist the area belongs to their Islamic leader.
The leader, Jamalul Kiram III, 74, claims to be the heir to the Islamic sultanate of Sulu, which once controlled parts of the southern Philippines and the Malaysian state of Sabah on Borneo.
Malaysian media also quoted Ismail saying that police were pursuing yet another group of armed men in Kunak, another town in the area.
The fresh developments have sparked Malaysian fears of a possible wider campaign of violence by supporters of the group in Sabah, which has large numbers of Filipino immigrants, both legal and illegal.
Officials issued calls for calm as some stores in the region reported panic buying of goods.
"I am calling for cooperation and assistance from local leaders to tone down the sentiments and numerous rumours on what is happening in Sabah," the state's chief minister Musa Aman was quoted saying by Malaysian media.
Earlier on Sunday, Sabah police chief Hamza Taib was quoted as confirming the latest clash was linked to the ongoing siege in the village of Tanduo, which is hours away by road. Reports provided no further details.
Ismail said, however, it remained unclear whether there was any link.
The situation is a highly delicate one for the Southeast Asian neighbours.
The Philippine government is looking to consolidate recent progress in mending fences with Islamic separatists in its predominantly Muslim south.
Muslim-majority Malaysia, meanwhile, could face pressure at home for taking harsh action against the Islamic intruders.
Following Friday's initial fire fight, Malaysian police threatened "drastic action" to clear out the trespassers.
Philippine President Benigno Aquino, who has sharply criticised the intruders, also urged them to surrender unconditionally.
But Kiram's spokesperson, Abraham Idjirani, repeated on Sunday that his followers would not budge.
He added the sultan would seek US intervention, citing a past agreement with Washington, which controlled the Philippines in the early 1900s.
"(Malaysia) want to hide the truth, that they do not own Sabah. It is owned by us," he said.
US embassy officials in Manila were not immediately available to comment.
The stand-off has embarrassed Malaysian Prime Minister Najib Razak - who must call elections by June - by exposing lax border security and fuelling perceptions of lawlessness and massive illegal immigration in Sabah.
His long-ruling government was already on the defensive over allegations that in the 1990s it gave citizenship to possibly hundreds of thousands of illegal Filipino and Indonesian migrants in Sabah in exchange for their votes.
The Sulu sultanate's power faded about a century ago but it has continued to receive nominal payments from Malaysia for Sabah under a historical lease arrangement passed down from European colonial powers.
Kiram's people are demanding Malaysia recognise the sultanate owns Sabah and share profits from economic development in the state.