Atleast 65,000 Rohingya have fled to Bangladesh from Myanmar, a third of them over the past week, since the army launched a crackdown in the north of Rakhine state, the UN said today.<br/><br/>The figure marks a sharp escalation in the numbers fleeing a military campaign which rights groups say has been marred by abuses so severe they could amount to crimes against humanity.<br/><br/>They also come the same day the UN's human rights envoy for Myanmar, Yanghee Lee, began a 12-day visit to probe violence in the country's borderlands that will take her to the army-controlled area.<br/><br/>As of 5 January, an estimated 65,000 people are residing in registered camps, makeshift settlements and host communities in Cox's Bazaar in southern Bangladesh, said the Office for the Coordination of Humanitarian Affairs.