Cox's Bazar (Bangladesh): At least five people were killed and dozens left missing today after a boat packed with Rohingya refugees fleeing Myanmar's Rakhine state for Bangladesh sank in a river that separates the two nations, a border guard official said. 

The tragedy is the latest to hit Rohingya escaping what the UN has called "ethnic cleansing" by Myanmar authorities.  

Nearly 200 people have died in around a dozen boats sinkings since the Rohingya influx began in late August after attacks my Muslim militants triggered what the Myanmar military has labelled "clearance operations". 

"The boat was carrying around 50 people when it sank on the estuary of the Naf river in the morning. Five bodies were found including four children, and 21 people survived," Border Guard Bangladesh area commander Lieutenant Colonel S M Ariful Islam told AFP. 

Islam said the boat was a small fishing trawler, which sank as it was overloaded with refugees who are often charged exorbitant fees for the trip to Shah Porir Dwip, a Bangladesh coastal village, across from the Myanmar border. The coast guard and border guards were conducting a search and rescue operation in the Naf river, he said.   

It sank just about a week after another boat packed with Rohingya capsized in the estuary of the Naf river, that has become a graveyard for Muslim refugees trying to escape Myanmar. 

At least 34 bodies have been washed up to Bangladeshi coastal villages and its southernmost Saint Martin Island after a boat carrying between 60 and 100 people sank after being swept by high waves.   

The UN estimates that some 537,000 Rohingya have fled to camps and makeshift settlements in Bangladesh in the fastest growing refugee crisis. Many of those who came to Bangladesh travelled on rickety fishing trawlers over rough water in the Naf river and perilous seas in the Bay of Bengal.