File Photo: A Rohingya refugee woman holds her child at a temporary shelter in East Aceh, Indonesia, May 21, 2015. (Xinhua/Junaidi)

UNITED NATIONS, Sept. 28 (Xinhua) -- UN Secretary-General Antonio Guterres on Thursday called for action from the Security Council to end the tragedy in Rakhine State of Myanmar.

"The reality on the ground demands action -- swift action -- to protect people, alleviate suffering, prevent further instability, address the roots of the situation and forge, at long last, a durable solution," he told the Security Council.

"I call on the Security Council to stand united and support our efforts to urgently end this tragedy," he said, when briefing the 15-member council on the situation in Rakhine.

Guterres said the crisis has steadily deteriorated since the Aug. 25 attacks by the Arakan Rohingya Salvation Army on the Myanmar security forces. "Since then, the situation has spiraled into the world's fastest developing refugee emergency, a humanitarian and human rights nightmare," he said.

At least 500,000 civilians have fled their homes and sought safety in neighboring Bangladesh. Although the total number of those displaced is unknown, it is estimated that 94 percent of them are Rohingyas, a mostly Muslim ethnic minority living in the largely Buddhist nation of Myanmar.

He called on the Myanmar authorities to take three immediate steps: to end the military operations; to allow unfettered access for humanitarian support; and to ensure the safe, voluntary, dignified and sustainable return of the refugees to their areas of origin.

It is the first open meeting of the Security Council on the situation in Rakhine since Aug. 25. It came after Guterres, the former head of the UN refugee agency, wrote an official letter on Sept. 2 to the Security Council to express his concern, the first such communication between a secretary-general and the council in 28 years.

The Myanmar ambassador to the United Nations, Hau Do Suan, on Monday denied ethnic cleansing in Rakhine, saying Rohingya rebels conscripted Muslim men and intimidated women and children to flee into neighboring Bangladesh to call attention to their cause.

"Let me be clear: there is no ethnic cleansing; there is no genocide," the envoy spoke at the end of the annual UN General Assembly General Debate, exercising his right of reply.