The 15-member Security Council met behind closed doors on Wednesday, at the request of Sweden and Britain, to discuss the crisis for the second time since it began and agreed to publicly condemn the situation.
Speaking before the meeting, Antonio Guterres called the situation for the Rohingya refugees "catastrophic" and "completely unacceptable", acknowledging that the minority group was being ethnically cleansed in the Buddhist-majority nation.
Around 370,000 of Myanmar's minority Rohingya population have fled the country's western state of Rakhine into neighbouring Bangladesh in recent weeks, according to the UN.
The violence began on August 25, after Rohingya fighters attacked police posts, prompting a military crackdown.
"I call on the Myanmar authorities to suspend military action, end the violence, uphold the rule of law and recognise the right of return of all those who have had to leave the country," the UN chief said at the press conference in New York.
|Rohingya refugees from Myanmar gesture towards a man on a truck delivering food aid in Ukhia, Bangladesh [Munir Uz Zaman/AFP]|
Al Jazeera's Rosiland Jordan, reporting from the UN headquarters, said it remains to be seen if the Security Council can do anything from a practical standpoint following Wednesday's meeting.
"There is a lot of concern here at the UN about the ongoing crisis," she said. "The question is: who can be held accountable and can the situation be resolved quickly, or is there going to be another looming humanitarian catastrophe?"
The council "expressed concern about reports of excessive violence during the security operations and called for immediate steps to end the violence in Rakhine, de-escalate the situation, re-establish law and order, ensure the protection of civilians ... and resolve the refugee problem."
British UN Ambassador Matthew Rycroft said it was the first statement from the Security Council on Myanmar in nine years.
This comes as Myanmar's national leader Aung San Suu Kyi cancelled her trip to next week's UN General Assembly to deal with the crisis, her office said on Wednesday.
She is due to give her first speech on the situation in a televised address next week.
Aung San Suu Kyi has been widely condemned for lack of moral leadership and compassion in the face of the crisis, denting the Nobel Peace Prize laureate's reputation.
The secretary-general also said he has spoken to Aung San Suu Kyi several times.
Pressure has been mounting on Myanmar to end the recent surge in violence, with the United States calling for protection of civilians and Bangladesh urging safe zones to enable refugees to go home.
Asked if the situation could be described as ethnic cleansing, Guterres replied: "Well I would answer your question with another question: When one-third of the Rohingya population had to flee the country, could you find a better word to describe it?"
Myanmar's government said on Wednesday that 176 Rohingya villages were completely empty as residents fled the recent upsurge in violence.
"This is a dramatic tragedy," Guterres said. "People are dying and suffering at horrible numbers, and we need to stop it. That is my main concern."
The government says about 400 people have been killed in the latest fighting in the western state.
Guterres called on the authorities to allow the UN and NGOs into Rakhine State to provide humanitarian aid.
The UN describes the Rohingya as the world's most persecuted people.
The Rohingya have suffered years of discrimination and have been denied citizenship in Myanmar since 1982.
But Guterres said that the Myanmar government should either grant the Rohingya nationality or legal status that would allow them to live a normal life.
Source: Al Jazeera and news agencies