Image copyright AP Image caption At least 86 Rohingya have been killed and more than 27,000 forced to flee military operations in Rakhine

The headless body of a Rohingya Muslim man has been discovered days after he spoke with reporters about unrest in Myanmar's Rakhine state, officials say.

The body of the 41-year-old was found floating in a river on Friday.

His family raised concerns on Wednesday after he spoke to Burmese journalists about attacks on security forces.

Police said they were still investigating. The area has been under lockdown for more than two months since militants attacked border posts.

During a rare media tour of the area, the man spoke to reporters about army repression and said local villagers had been involved in attacks, the BBC has learned.

Rakhine state is home to Myanmar's Muslim Rohingya minority, one of the world's most persecuted minority groups.

Amnesty International has accused Burmese security forces of rape, murder, and torture.

Myanmar's military has denied accounts of atrocities and says it is conducting anti-terrorist raids in Rakhine.

Troops took control of the dangerous and remote region bordering Bangladesh after armed men raided police posts, killing nine officers, in October.

The government of Myanmar, also known as Burma, says it is conducting counter-terrorism operations in the region but has denied reports of atrocities.

Most of the displaced Rohingya have fled across the border into Bangladesh.

Who are the Rohingya?

The estimated one million Muslim Rohingya are seen by many in mainly Buddhist Myanmar as illegal migrants from Bangladesh. They are denied citizenship by the government despite many having lived there for generations.

Communal violence in Rakhine state in 2012 left scores dead and displaced more than 100,000 people, with many Rohingya still remaining in decrepit camps.

They face widespread discrimination and mistreatment.

Hundreds of thousands of undocumented Rohingya are estimated to live in Bangladesh, having left Myanmar over decades.