The police officer was killed when he was fired upon Saturday in the Malaysian town of Semporna, 300 kilometres (190 miles) by road from the site of the standoff at Tanduo village on Borneo island where 12 Filipino intruders and two police died in a firefight the day before.
State news agency Bernama also said another officer suffered gunshot wounds.
It quoted police saying the killing was unrelated to the nearly three-week siege involving armed intruders who arrived from the Philippines by boat to press the “sultan’s” historical claim to the area.
But the latest shooting raised fears on Malaysian social media sites of a possible spread of violence by suspected sympathisers of the group.
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 to insist the area belongs to their Islamic leader Jamalul Kiram III’s.