Corpses in rows
The army said that security officers found a total of 20 dead women and eight men in two graves, including six boys under the age of ten.
A strong smell led security officers to the burial site outside of Ye Baw Kya village, the army said.
Unverifiable photos published by the government's Information Committee showed corpses laid out in rows on grass near two mud pits where they were found.
Myanmar government spokesman Zaw Htay confirmed the grim discovery to AFP, as did a senior police officer in Rakhine who requested anonymity.
The village where the bodies were found, Ye Baw Kya, lies near a cluster of Hindu and Muslim communities in northern Rakhine called Kha Maung Seik.
Last week Hindus from the area told AFP that militants swept into their villages on August 25 with sticks and knives, attacking people who stood in their way, killing many and taking others into the forest.
Hindu women are believed to have been abducted by the militants.
The grim discovery of the graves will further fuel already white-hot hatred between ethnic groups in Myanmar.
The epicentre of the unrest, in northern Rakhine, is dominated by Rohingya Muslims who are a minority elsewhere and have been the target of decades of state-backed persecution and discrimination.
Around half of their estimated 1.1 million population has fled over the last year.
Northern Rakhine is also home to ethnic Rakhine Buddhists, Hindus and a myriad of other groups.
Religious tensions have simmered for years, erupting into sporadic bouts of violence.
But the scale of the latest unrest is the worst to hit the region in years.
While the wretched lines of Rohingya streaming into Bangladesh have shocked and alarmed the world, there is scant sympathy for the Muslim group inside Myanmar.
Many in the Buddhist majority view the group as illegal immigrants from Bangladesh, despite their long-established roots in the country.