"What we are seeing in Rakhine State is a land grab by the military on a dramatic scale", Tirana Hassan, Amnesty's crisis response director, said in a statement, adding how the new construction makes the much-debated return of Rohingya refugees even more impossible.
"Not only are their homes gone, but the new construction is entrenching the already dehumanizing discrimination they have faced in Myanmar", Hassan added.
The new Amnesty report, "Remaking Rakhine State", uses satellite imagery and interviews to point to a rapid increase in military infrastructure and other construction since the start of the year that researchers say amounts to a "land grab". "But the reality is that they are often building on top of these former villages", he said.
Lee was speaking as her scathing report on the state of human rights in Myanmar was released, in which she calls for calls "for a thorough, impartial and credible investigation to be conducted without delay and perpetrators to be held responsible for the alleged crimes that were committed in Rakhine State". "No one wants to stay because they are afraid of more violence against them", said a 31-year-old man who fled to Bangladesh in January when the military erected a new fence and security post close to his village.
A top United Nations rights expert said the crackdown on Myanmar's Rohingya minority bears "the hallmarks of genocide", as a new report accuses Myanmar's military of building bases where some of the Rohingya homes once stood. By January 2018, a new road has been built directly on land where Rohingya homes had stood.
"I am becoming more convinced that the crimes committed following 9 October 2016 and 25 August 2017 bear the hallmarks of genocide and call in the strongest terms for accountability", said Yanghee Lee, the Special Rapporteur on human rights in Myanmar.
Myanmar's envoy Htin Lynn rejected Lee's remarks and called for the council to fire her.
The new developments also include a "transit center" meant to house returning Rohingya refugees, that was built on top of a burned-out village, Amnesty said.
Lee also warned of new offensives in the states of Kachin and Kayin, east of Rakhine.
Facebook has played a role in spreading hate speech in Myanmar, UN human rights experts investigating a possible genocide against Rohingya Muslims said.
The development has raised questions over the safety of hundreds of thousands of persecuted Rohingyas due to be repatriated from neighbouring Bangladesh to Myanmar.
The UN human rights chief said last week he strongly suspected acts of genocide had taken place, while Myanmar's national security adviser demanded "clear evidence". "As far as the Myanmar situation is concerned, social media is Facebook, and Facebook is social media", he said.