(Reuters) - A group of Papua New Guinea soldiers mutinied on Thursday, seizing and replacing their chief commander in what could be a ploy to help former prime minister Sir Michael Somare return to power, the Australian Broadcasting Corp (ABC) reported.
The South Pacific nation has been plagued by political instability for weeks, jeopardizing its prospects as an investment destination just as U.S. oil giant ExxonMobil develops a $15.7 billion liquefied natural gas plant, the country's biggest-ever resource project.
Twelve to 20 rebel troops raided the headquarters of the defence forces, Murray Barracks, in the capital in the early hours of the morning, put Brigadier General Francis Agwi under house arrest and replaced him with a new commander, ABC said.
It added that a former defence attaché to Indonesia, a Colonel Safa, had since declared himself as new commander.
There were no immediate reports of violence at the barracks or in the streets of Port Moresby.
Neighboring Australia appeared to confirm the move against Brigadier General Agwi, calling for a restoration in the line of command in Papua New Guinea's defence forces.
"We urge that the situation be resolved as soon as possible, and that the Papua New Guinea Defence Force chain of command is restored," the foreign ministry said in a statement.
It added, however, that an Australian diplomat had even spoken to Agwi since his seizure, lending weight to reports that Papua New Guinea authorities were trying to calm the situation. The ABC said Agwi was under "house arrest."
The initial, sketchy reports followed weeks of political instability, with Somare challenging the legitimacy of Prime Minister Peter O'Neill's government. Somare had been replaced by O'Neill last August after his seat was declared vacant while he received medical treatment in Singapore.
The ABC also speculated whether the mutiny could instead be related to unhappiness within the ranks over pay and conditions following cutbacks to defence spending. It noted that some soldiers had been planning to stage a protest in coming days.
"At this stage it is not clear if the incident is related to the conflict between Peter O'Neill and Sir Michael Somare over the country's prime ministership, or if it is the work of disgruntled soldiers," ABC said on its Web site.
Last month, O'Neill declared victory in the standoff after the governor general named him the legitimate head of government. The country's civil service, police and army leaders also backed O'Neill, though the ABC speculated that some sections of the army could still be supportive of Somare.
For many Papua New Guineans, the crisis is a contest between the old political guard of Somare -- known as "The Chief" who led the country to independence -- and O'Neill's administration, which is seen offering a fresh, more open alternative.
Elections are due in June.
(Reporting by Lincoln Feast; Writing by Mark Bendeich; Editing by Sanjeev Miglani)