The army appointed a senior officer to investigate.
Both the United Nations and USA have stated that he military's action has amounted to ethnic cleansing of the Rohingya Muslim minority in majority Buddhist Myanmar.
As per Anadolu news agency, the request comes after the military admitted to the killing of 10 Rohingyas in the war-ravaged Rakhine state.
The results of an internal military investigation found that soldiers, along with local villagers, were culpable for the deaths of the Rohingya, who the military labeled "terrorists", according to a statement posted to the Facebook page of Myanmar's Commander-in-Chief.
James Gomez, Amnesty's regional director for Southeast Asia and the Pacific, called the admission a positive development, but said it was "only the tip of the iceberg".
Amnesty International described the statement as "a sharp departure from the army's policy of blanket denial of any wrongdoing".
Many refugees start at transit centres set up along the Bangladesh-Myanmar border before they are brought to the main refugee camps in Cox's Bazar.
Since the August crackdown the army vigorously denied any abuses, instead locking down access to Rakhine state and accusing critics, including the United Nations, of pro-Rohingya bias and spreading "fake news".
Inn Din, the site of the mass grave, was one of the hundreds of villages that was engulfed by violence during the August crackdown.
The military claimed they had rushed to Inn Din to protect frightened Buddhist villagers and had been attacked by "200 Bengalis" with sticks and swords, 10 of whom were arrested and accused of having links to terrorists. The use of the term "Bengali" is the commonly used term for Rohingya in Burma as it implies they are illegal immigrants from Bangladesh, despite them living in Burma for generations.
Ten of the assailants were captured, but "it was found that there were no conditions to transfer the 10 Bengali terrorists to the police station and so it was made a decision to kill them", the military said, and vowed to take action against those involved in the killing. "Such behaviour shows a contempt for human life which is simply beyond comprehension", he said.
Ro Nay San Lwin, a Rohingya activist, said he did not believe the army's account of the incident.
Some observers say the army move is an attempt to retake control of the story after rumours of extra-judical killings at Inn Din and the surrounding area began to seep out.
"I have spoken to many eye witnesses".
Rohingya Muslims who fled a village where Myanmar has admitted its forces helped massacre 10 people said Thursday the victims were all civilians, not fighters as asserted by the Tatmadaw.
Robertson warned that the admission it did not represent a change of heart from the military.