The United Nations says the number of Rohingya Muslims who have fled from Myanmar is now up to 589,000.

Seven thousand crossed into Bangladesh on Friday. Over the past two months, religious and ethnic tensions in the nation once known as Burma have exploded.

BBC News' Clive Myrie reports from Bangladesh.

Every breath is a struggle for six-month-old Mohammad Ibrahim, who is fighting pneumonia. He's terribly weak and malnourished. He has just a 50/50 chance of seeing out another day.

Eighty percent of the patients at one medical center in Bangladesh are Rohingya Muslim refugees, and many are malnourished children -- the weakest of the weak.

The mother of 18-month-old Moshtakima summed up the nightmare of so many Rohingya women.

"We had to run from our village," she said. "But we had so little to eat. Then when we managed to get food. I couldn't feed my child. She's so sick."

Ian Cross, a former general practitioner from Leicester, Britain, is working with local medical staff.

"Tears come to my eyes sometimes," Cross said. "It's dreadful."

It is a depressing truth in this crisis that close to 60 percent of the 589,000 Rohingya Muslims who have escaped Myanmar are children and teenagers.

The chance of children falling into the hands of sexual predators or exploited for their labor is ever-present.

This mother said she had to flee her village when she finally did get food, she couldn't feed her daughter. BBC News

"The families here have nothing," said UNICEF's Christophe Boulierac. "They are trying to survive on a daily basis. And some of them at some point might be tempted to give away one of their child for domestic work. You know, not going to school, sometimes sexual abuse."

But there is light amidst all the gloom. Children in the camps are getting vaccinated against cholera and other diseases. There's even a chance to watch cartoons.

Outside one refugee camp, BBC News found 9-year-old Mimouna by the side of the road, cradling her younger brother Abu, too young to understand the bundle in her arms was severely malnourished.

UNICEF was alerted, and doctors are now treating them both.

But some will never have the chance to return to Myanmar.

The day after BBC News filmed Mohammed Ibrahim, he had died.

