The number of Muslim Rohingya who have crossed into Bangladesh to escape ethnic unrest in Myanmar since August 25 hit 389,000 on Thursday, a UN spokesman said.
The figure rose 10,000 in 24 hours, indicating the Rohingya crisis remains acute.
UN refugee agency spokesman Joseph Tripura gave AFP the latest number. Other UN agencies have sounded the alarm over conditions for the Rohingya who have fled a military crackdown in Buddhist-dominated Myanmar's Rakhine state.
Most of the influx is concentrated around the Bangladesh border town of Cox's Bazar where more than 300,000 Rohingya refugees were packed into ill-equipped camps before the violence erupted last month in Rakhine.
The UN children's agency, UNICEF, says that 60 per cent of the new arrivals are children.
"There are acute shortages of everything, most critically shelter, food and clean water," said Edouard Beigbeder, UNICEF's representative in Bangladesh, in a statement.
"Conditions on the ground place children at risk of high risk of water-borne disease. We have a monumental task ahead of us to protect these extremely vulnerable children," said the official.
Azizul Haque died in a Bangladeshi hospital on Thursday, a week after his body was torn apart by a landmine he stepped on as he and his Rohingya Muslim family fled Myanmar.
The 15-year-old lost both his legs in the blast near the border. Myanmar is one of the last countries in the world to actively use landmines. The explosion and cuts and shrapnel wounds across most of his body had left Haque in agony.
The youth remained in a desperate state despite several operations and an administrator at a charity hospital in Cox's Bazar, focus of the mounting Rohingya refugee crisis, confirmed Haque passed away there early today.
His brother was also injured in the blast but joined the family when they went to the hospital to collect the body.
Haque's mother, Rashida Begum, spent days at the bedside of her son. He could barely muster enough energy to ask for a fruit juice. She did not have enough to pay for it anyway.
In the hours before his death, she tearfully recounted to AFP how the family had escaped their home village only to face devastation at the frontier.
The family are among almost 400,000 Rohingya Muslims who have sought refuge in Bangladesh from violence in Buddhist- dominated Myanmar's Rakhine state that started August 25.
They had to run away from their home village of Debinna in Rakhine.
"Everyone was in a rush. Nobody could look out for others as the Burmese were chasing us from behind and burning the village," the mother of four said.
They were in sight of the Bangladesh frontier when Azizul Haque set off the landmine.
"We heard a huge explosion as Azizul stepped on the mine," said the mother. "I saw his two legs blown away."
While many Rohingya refugees have recounted tales of torture and rape by Myanmar troops and Buddhist militias as they escaped, landmines are the latest deadly threat to come to light.
Senior Bangladeshi officials believe anti-personnel mines, which were banned by a 1997 global treaty, have been planted by Myanmar security forces to prevent Rohingya from trying to return to their villages.
"Since September 3, we have heard at least 12 landmine explosions. At least three people were killed and seven were injured in the blasts," Border Guard Bangladesh Commander Manzurul Hasan Khan told AFP.
Haque is the fourth known death.
"All indications point to the Myanmar security forces deliberately targeting locations that Rohingya refugees use as crossing points," said Tirana Hassan of Amnesty international.
"This a cruel and callous way of adding to the misery of people fleeing a systematic campaign of persecution," she said.
The UN Security Council yesterday called on Myanmar to end to the crackdown on the Rohingya, as UN chief Antonio Guterres said the military campaign amounted to ethnic cleansing of Rohingya Muslims.
The 1.1-million strong Rohingya have suffered years of discrimination in Myanmar, where they are denied citizenship even though many have long roots in the country.
Border guards let Haque's family enter when they carried the stricken boy to the fence.
"We rushed him to a nearby Doctors Without Borders clinic and they referred us to this hospital," said his mother Rashida.
Surgeons conducted multiple operations on Haque, but said his chances were never good.
Haque was just one of at least 20 Rohingya victims of bullet wounds, burns and bomb explosions being treated at the Cox's charity hospital.
Several others, including Haque's brother were injured in the same mine incident.
Sabekun Nahar, 50, suffered leg injuries after she stepped on a suspected landmine near where Haque was blown up.
"I wonder how I will ever walk again," she said, tears welling in her eyes. (Courtesy AFP)