An unprecedented 200,000 child refugees have fled Burma and are now in urgent need of help, Unicef has warned, as the Rohingya crisis reaches new proportions.

Minors make up at least 60 per cent of the 330,000 Rohingya who have crossed the border to Bangladesh over the past few weeks. Highly traumatised, they are arriving malnourished and injured after walking for days, a spokesperson said.

Speaking to The Independent shortly after visiting the Burmese border, Unicef communications chief for south Asia Jean-Jacques Simon said it was hard to imagine what the "streams" of people crossing had witnessed.

"It's reaching a new proportion every day... You have to wonder when it will stop," he said.

Mr Simon said he had seen children as young as three arrive in Bangladesh without their parents. "Was it because the parents put them forward for the crossing, or was it something else?" he asked, alluding to the reports of large-scale violence.

This week, UN Secretary-General Antonio Guterres urged Burma to end the violence, which he called "ethnic cleansing."

“Grievances that have been left to fester for decades have now escalated beyond Myanmar's [Burma's] borders, destabilising the region,” he warned. “The humanitarian situation is catastrophic.”

Rohingya refugees – in pictures Show all 15 1 /15 Rohingya refugees – in pictures Rohingya refugees – in pictures A young girl and a baby wade through mud after arriving in Whaikhyang, Bangladesh from Burma on 10 September Dan Kitwood/Getty Images Rohingya refugees – in pictures Rohingya refugees walk through a camp in Whaikhyang, Bangladesh after arriving from Burma Dan Kitwood/Getty Images Rohingya refugees – in pictures A young Rohingya refugee gathers firewood after arriving in Whaikhyang, Bangladesh from Burma Dan Kitwood/Getty Images Rohingya refugees – in pictures Rohingya refugees wait for sacks of rice to be distributed in Whaikhyang, Bangladesh Dan Kitwood/Getty Images Rohingya refugees – in pictures Rohingya Muslim refugees arrive on a boat in Whaikhyang, Bangladesh after crossing from Burma on 8 September Dan Kitwood/Getty Images Rohingya refugees – in pictures Rohingya Muslim refugees react after being re-united with each other after arriving in Whaikhyang, Bangladesh on a boat from Burma Getty Rohingya refugees – in pictures Rohingya Muslim refugees walk along the remains of a road after arriving in Whaikhyang, Bangladesh on a boat from Burma Dan Kitwood/Getty Images Rohingya refugees – in pictures Rohingya Muslim refugees wade through water after arriving in Whaikhyang, Bangladesh by boat from Burma Dan Kitwood/Getty Images Rohingya refugees – in pictures Rohingya Muslim refugees wade through water after arriving in Whaikhyang, Bangladesh by boat from Myanmar Dan Kitwood/Getty Images Rohingya refugees – in pictures Rohingya Muslim refugees stand in the rain after arriving in Whaikhyang, Bangladesh by boat from Burma Dan Kitwood/Getty Images Rohingya refugees – in pictures Indian children hold placards and shout slogans during a protest against the alleged persecution of the Rohingya Muslims in Burma EPA/Raminder Pal Singh Rohingya refugees – in pictures Supporters of the Difa-e-Pakistan Council (DPC), an Islamic organisation, listen to their leaders' speeches against Burma's persecution of Rohingya Muslims, during a demonstration in Karachi Reuters/Akhtar Soomro Rohingya refugees – in pictures Hundreds of Iranians take part in a protest against violence in Myanmar after weekly Friday prayers, in Tehran EPA/Abedin Taherkenareh Rohingya refugees – in pictures Indonesian Muslim activists hold placards and shout slogans during a protest against the alleged persecution of the Rohingya minority in Magelang, Central Java, Indonesia EPA/Ali Lutfi Rohingya refugees – in pictures Members of an Islamic organisation shout slogans against the Burma government during a protest in Dhaka, Bangladesh EPA

On the ground, the scale of need is desperate, Mr Simon explained, speaking from Cox's Bazar, where tens of thousands of refugees are camping in makeshift tents and more are constantly arriving. "They need to find shelter, they need to find food."

Many of the children are displaying classic signs of trauma, including shaking and an inability to interact with other people.

"I saw two days ago two unaccompanied children, they were together," Mr Simon said. "They had obviously been in mud for a long time, they were holding each other's hands.

"It was very sad," he continued. "They were basically speechless. They were staring, we asked questions about their parents and they stared without being able to speak. They were just shaking."

Unicef is offering counselling for Rohingya children in mobile clinics that travel between refugee camps. They are given pencils and paper if they can't speak, Mr Simon said. Sometimes the children will start drawing pictures of the chaos and destruction they saw before they left.