High-definition satellite images show 820 newly identified structures destroyed in five Rohingya Muslim villages in the Myanmar's troubled Rakhine state this month where the military is carrying out counter-insurgency operations, according to Human Rights Watch (HRW).
In a statement released on Monday, the US-based group urged the government to invite the United Nations to assist in an impartial investigation.
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"These alarming new satellite images confirm that the destruction in Rohingya villages is far greater and in more places than the government has admitted," said Brad Adams, HRW's Asia director.
Myanmar president's spokesman accused HRW of exaggeration last week after the release of an initial set of satellite imagery that showed 430 destroyed buildings in three villages.
He accused the international media of misreporting the situation in Rakhine, where the government has mounted a massive, ongoing security operation since nine police officers were killed by unidentified assailants who attacked guard posts in Maungdaw village bordering Bangladesh last month.
The government has acknowledged using helicopter gunships in support of ground troops in the operations.
Rohingya Muslims face intense discrimination, repression and violence in Rakhine state. Viewed as illegal migrants, they have frequently been targeted by the Buddhist Rakhine majority.
The state refuses to grant them citizenship even though they have lived in the region for generations.
More than 100,000 Rohingya still live in camps after being driven from their homes following clashes with the Rakhine people in 2012.
'Hundreds of arrests'
HRW said the new satellite imagery - recorded on November 10, 17 and 18 - brings the number of destroyed buildings documented by it to 1,250.
Ko Ko Linn, an activist of Arakan Rohingya National Organisation, said hundreds of arrests have been made, at least 1,000 houses in Maungdaw burned down and more than 100 people have been killed.
These claims, however, are impossible to verify, as are the government allegations because of access restrictions on journalists and aid workers.
On Friday, the UN warned of a worsening rights situation in Rakhine state.
Tens of thousands of people have fled their homes amid the security operation.
Humanitarian assistance has been suspended and civilians are reported to be caught up in military action, and there are reports of human rights abuses, including the alleged rape and sexual assault of women and girls.