The man claiming to be in charge of Papua New Guinea's military has given the nation's politicians seven days to decide who is in charge of the country.
Retired Colonel Yaura Sasa says he has taken control of PNG's military following discussions with Brigadier General Francis Agwi.
Both men had been appointed by Sir Michael Somare.
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The ABC reported a group of about a dozen soldiers staged a mutiny in the early hours of Thursday morning.
Somare lost office last August after parliament voted to end his
nine year run as prime minister.
But in December the Supreme Court reinstated him, leading to a week-long crisis which resulted in rival Peter O'Neill in charge of government.
"My task is restoring the integrity and respect of the constitution and the judiciary," he told reporters from the commander's office in Port Moresby's Murray barracks on Thursday.
"I am now calling on the head of state (Governor General Sir Michael Ogio) to immediately implement Sir Michael's post as prime
minister."
He said Mr O'Neill must recall parliament and gave PNG's 109 MPs a seven day deadline to "sort out" the constitutional mess.
The gates of Murray barracks have been locked down with O'Neill expected to go to the barracks with troops loyal to him.
The Australian Department of Foreign Affairs and Trade (DFAT) has advised Australians to limit travel around Port Moresby on Thursday "due to disturbances at Murray and Tarama Barracks".
