unite nations unite nations secretary-general antonio guterres warn thursday violence myanamar rohingya muslims northern part rakhine state could spread central rakhine 250,000 people risk displacement guterres tell u.n. security council first public meet myanmar eight years violence spiral world fast develop refugee emergency humanitarian human right nightmare receive bone-chilling account flee mainly women children elderly say testimonials point excessive violence serious violations human right include indiscriminate fire weapons use landmines civilians sexual violence 500,000 rohingya muslim flee bangladesh past month since insurgents attack security post near border trigger fierce myanmar military retaliation unite nations brand ethnic cleanse sweden unite state britain france egypt senegal kazakhstan request thursday council meet guterres demand immediate humanitarian aid access areas affect violence express concern current climate antagonism towards unite nations aid group failure address systematic violence could result spill-over central rakhine additional 250,000 muslims could potentially face displacement guterres say crisis generate multiple implications neighbor state large region include risk inter-communal strife surprise decades discrimination double standards treatment rohingya create open radicalization say myanmar violence could spread displace rohingya u.n. chief