Sahany said the Rohingya crisis was not an issue between Myanmar and Bangladesh but of worldwide concern.
Myanmar's security forces responded by launching counterterrorism operations against insurgents.
The United States today told Myanmar that its security forces must refrain from attacking civilians and aid workers in its response to attacks by Rohingya militants in Rakhine state.
Violence has again engulfed Myanmar's volatile Rakhine state, killing scores of people and stoking fears that the long-running crisis there has grown more intractable and more likely to foster radicalization. Bangladesh is also growing increasingly hostile to Rohingya, more than 400,000 of whom live in the poor South Asian country after fleeing Myanmar since the early 1990s.
Thai Prime Minister Prayut Chan-ocha told reporters Thailand is preparing to receive refugees and "send them back when they are ready".
While the world's Muslim communities celebrated Eid al-Adha, the Rohingya remained in a precarious situation, not knowing their future or the fate of their relatives, she said.
While thousands of Rohingya refugees have made it across the border to Bangladesh, thousands of others are stranded in a no man's land between the two countries, the International Organization for Migration said.
When asked, Border Guard Bangladesh (BGB) Commanding Officer SMS Ariful Islam said: "We have not heard about the boat capsize but we have been informed that four bodies were seen off the shore". "When huge waves tilted the boat, we panicked", said Shah Karim.
The military's current offensive follows reported attacks on 30 police stations by a small armed group known as the Arakan Rohingya Salvation Army (ARSA) in Rakhine State on 25 August.
"I am concerned that these events will derail efforts to address the root causes of the systematic discrimination and recurrent violence in Rakhine State", said the Special Rapporteur.
"What we're hearing is burning, burning, burning", she said. There have been numerous eyewitness accounts of summary executions, rapes, and arson attacks by security forces against the Muslims since the crackdown began. He said that border guards provided them with food and medicine before pushing them back, but it was not clear what happened to them later.
A Rohingya villager near the town of Maungdaw, speaking on condition of anonymity, said residents fled his hamlet as security forces approached and torched their homes.