Story highlights Bill Richardson is the former Democratic Governor of New Mexico

He is a long time supporter of Aung San Suu Kyi and Myanmar

(CNN) One of Aung San Suu Kyi's closest allies has resigned from an international advisory board calling it a "cheerleading squad for government policy" that's failing to address the Rohingya crisis.

In a scathing statement released Thursday, Bill Richardson, the former US ambassador to the UN, accused Suu Kyi -- Myanmar's de facto leader, who he's known for decades -- of lacking "moral leadership."

"It appears that the Board is likely to become a cheerleading squad for government policy as opposed to proposing genuine policy changes that are desperately needed to assure peace, stability and development in Rakhine State," Richardson said.

As of August last year, more than 688,000 Rohingya have been forced to flee their homes in northern Rakine State amid widespread reports of military-backed mass rape, murder and the burning down of entire villages.

The UN and the US have labeled the violence against the mainly Muslim Rohingya as "ethnic cleansing."

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