UN investigators called Monday for Myanmars army chief to resign and for him and five other top military commanders to be prosecuted in an international court for genocide against the countrys Rohingya Muslim minority. A UN-backed fact-finding mission into violations in Myanmar said the countrys "top military generals, including Commander-in-Chief Senior-General Min Aung Hlaing, must be investigated and prosecuted for genocide in the north of Rakhine State." They should also be investigated and prosecuted for "crimes against humanity and war crimes" against the Rohingya in Rakhine, as well as against other minorities in the northern Kachin and Shan States, the mission said in a report. The army tactics have been "consistently and grossly disproportionate to actual security threats," it said. The call prompted Facebook, which has been criticized for allowing hate speech against the Rohingya to flourish, to ban the army chief and remove other pages tied to the countrys military.  Some 700,000 Rohingya fled Rakhine to Bangladesh after Myanmar launched a brutal crackdown in August last year amid accounts of arson, murder and rape at the hands of soldiers and vigilante mobs. Speaking to journalists in Geneva, the head of the UN mission, Marzuki Darusman, insisted that "the only way forward is to call for (Min Aung Hlaings) resignation and stepping down immediately." The mission, which was created by the UN Human Rights Council in March 2017, concluded in its report that "there is sufficient information to warrant the investigation and prosecution of senior officials in the Tatmadaw (Myanmar army) chain of command." "The crimes in Rakhine State, and the manner in which they were perpetrated, are similar in nature, gravity and scope to those that have allowed genocidal intent to be established in other contexts," it said. The investigators named six of the countrys top military commanders, adding that a longer list of names could be shared with "any competent and credible body pursuing accountability in line with international norms and standards." Criticism was also directed at Myanmars civilian leader Aung San Suu Kyi, a Nobel Peace Prize laureate who has been widely attacked for a perceived failure to stand up for the stateless minority. The report found that she had "not used her de facto position as head of government, nor her moral authority, to stem or prevent the unfolding events."  While acknowledging that the civilian authorities had little influence on military actions, it said they "through their acts and omissions ... have contributed to the commission of atrocity crimes." The investigators also found that soldiers had carried out "large-scale gang rape", sometimes of as many as 40 girls and women at once, in at least 10 Rakhine villages. "The Rohingya are in a continuing situation of severe, systemic and institutionali\ed oppression from birth to death," Darusman told reporters.