Updated

The U.N. human rights envoy for Myanmar has arrived in tense Rakhine state, where a military operation against Muslim insurgents has driven an estimated 65,000 people to flee into Bangladesh in the past three months.

U.N. rapporteur Yanghee Lee began a three-day mission there Friday. Members of the Muslim ethnic Rohingya minority say the military has tortured, raped and killed civilians and burned down their homes in northern Rakhine state. The army denies the abuse allegations, which have drawn worldwide concern.

Unverified claims by Rohingya sympathizers say hundreds have been killed.

The security crackdown began in October, after nine policemen were killed in attacks by a shadowy insurgent group along the border with Bangladesh.