Myanmar's defacto leader Aung San Suu Kyi is under mounting pressure over her handling of the crisis in the Rakhine State where nearly half a million of the Rohingya minority have fled in less than a month.
International leaders rounded on Suu Kyi after her address on Tuesday condemned rights abuses but did not blame the army or address allegations of ethnic cleansing.
Amnesty International branded the speech a 'mix of untruths and victim-blaming' and said it was evidence she and her government were 'burying their heads in the sand over the horrors unfolding in Rakhine state'.
South-east Asia regional director James Gomez said: 'If Myanmar has nothing to hide, it should allow UN investigators into the country, including Rakhine state. The government must also urgently allow humanitarian actors full and unfettered access to all areas and people in need in the region.'
The latest conflict comes after attacks on police outposts last month killed several officers and was blamed on the newly formed militant group Arakan Rohingya Salvation Army (ARSA).
But the issue has been ongoing with the largely Muslim 1.1million Rohingya in Myanmar considered the most persecuted group in the world.
In her first national address on the crisis Suu Kyi said most Muslims had stayed in Myanmar, indicating the situation was not as severe as reports suggests, insisting she does not 'fear international scrutiny'.
Speaking from the capital Naypyidaw she said: 'There have been allegations and counter-allegations ... We have to make sure those allegations are based on solid evidence before we take action.'
But US secretary of state Rex Tillerson urged Suu Kyi to allow humanitarian support into Rakhine State with aid agencies currently blocked from entering.
Speaking to the UN Assembly, French President Emmanuel Macron said 'the military operation must stop, humanitarian access must be guaranteed and the rule of law restored in the face of what we know is ethnic cleansing'.
Turkish President Recep Tayyip Erdogan joined the condemnation, calling on the international community to act warning 'unless the tragedy taking place in Myanmar is brought to a halt, humanity will have to live with the shame of another dark stain in its history'.
It comes as Christian Aid launched an appeal to help those affected, warning 210 villages have been destroyed in the north of the state and 'an unknown number of displaced people within Myanmar' on top of those who have fled.
Ram Kishan, the charity's regional manager, said: 'The number of refugees arriving in Bangladesh is rising rapidly - an estimated 15,000 people coming across the border daily – and now monsoon rains causing flooding in the makeshift camps are making the situation even worse. In Myanmar, internally displaced people in Central Rakhine haven't received regular assistance for days.
'Although civilians in the north of the state are not receiving regular aid, we have local partners there who can respond and scale up their efforts. The humanitarian needs on both sides of the border are mounting up.'
Head of humanitarian programmes Madara Hettiarachchi added: 'Now is the time to take action. The number of those who need humanitarian help is huge and we need to dramatically scale up our work not only for the initial response but for the long-term.'