United Nations (CNN) A day after the release of an independent United Nations investigation into alleged human rights abuses carried out against Rohingya Muslims, Secretary General António Guterres on Tuesday called for the Myanmar government to be held accountable for "one of the world's worst humanitarian and human rights crises."

The report, released in Geneva on Monday, contains accusations of murder, imprisonment and sexual violence against the Rohingyas, carried out by the Myanmar military, known as the Tatmadaw, under the guise of a crackdown on terrorists, and against a backdrop of impunity that effectively placed military leaders above the law.

"I believe this report's findings and recommendations deserve serious consideration by all relevant United Nations bodies," Gueterres said at a meeting of the UN Security Council. "Effective international cooperation will be critical to ensuring that accountability mechanisms are credible, transparent, impartial, independent and comply with Myanmar's obligations under international law."

US Ambassador Nikki Haley told her colleagues they "must hold those responsible for the violence to account."

But a representative from China said the United Nations should have a gradual and persistent approach.

"Given the current situation, the international community should cherish the hard-earned progress and the full understanding to the great difficulties faced by countries concerned," Deputy Permanent Representative Ambassador Wu Haitao said, "and continue to provide constructive assistance instead of simply putting pressure on them."

The meeting also featured an impassioned plea from famed actress Cate Blanchett, a UN goodwill ambassador for refugees who visited a Bangladesh camp. What she saw and heard were shocking, she said.

"There are no shortcuts. There are no alternatives. We have failed the Rohingya before. Please, let us not fail them again," Blanchett said

Myanmar disagreed with the report.

"I would like to reiterate that we did not accept the mandate of the mission because we have our concern about the mission's impartiality," Myanmar Ambassador to the UN Hau Do Suan said. "Besides, I have serious doubt on the intention of the timing of the release of the report."

He said the government does not condone human rights abuse, and will take action, if there is evidence of such crimes.

The government is united with the people to achieve peace, he said.

"We shall seek reconciliation, but not retribution. Compassion, but not hatred. Integration, but not segregation," he said.

Government blames militants for violence

Monday's report called for Myanmar's military leaders to be investigated and prosecuted for genocide, crimes against humanity and war crimes.

"Military necessity would never justify killing indiscriminately, gang-raping women, assaulting children, and burning entire villages. The Tatmadaw's tactics are consistently and grossly disproportionate to actual security threats, especially in Rakhine State, but also in northern Myanmar," the report said.

Myanmar's military has repeatedly denied that it has deliberately attacked unarmed Rohingya. Instead, the authorities say it only targets Rohingya militants, mostly from the Arakan Rohingya Salvation Army insurgent group, which has launched deadly attacks on police posts.

Zaw Htay, a spokesman for Myanmar's presidential office, told CNN via text message that Myanmar's government has already formed its own Independent Commission of Enquiry to investigate reports of human rights violations in northern Rakhine State since August 25, 2017.

He said Myanmar's government had previously "disassociated" itself from the UN's fact-finding mission, referring to a position taken by Myanmar authorities due to concerns it would "inflame" rather than "resolve" issues.

US: 'Unspeakable crimes'

Guterres said he visited Cox's Bazar in Bangladesh, where Rohingya refugee camps are located, last month and heard several stories of "horrendous persecution and suffering," including that of a father who saw his son shot dead in front of him.

"It is clear that conditions are not yet met for the safe, voluntary, dignified and sustainable return of Rohingya refugees to their places of origin or choice," Guterres said. "I ask members of the Security Council to join me in urging the Myanmar authorities to cooperate with the United Nations, and to ensure immediate, unimpeded and effective access for its agencies and partners. We must also continue to press for the release of journalists who have been arrested for reporting on this human tragedy."

Haley said the results of a US State Department report, in which investigators spoke to more than 1,000 Rohingya refugees, are consistent with the UN report.

"We are now all armed with the devastating eyewitness accounts of the Rohingya, which lead us to the following conclusions: Children, babies, women and men suffered unspeakable crimes. The attacks were planned, premeditated and coordinated. The perpetrator was the Burmese military and security forces," she said.

"The whole world is watching what we will do next, and if we will act," she added.

The report for the UN recommends the case be referred to the International Criminal Court in The Hague, Netherlands, or for an ad hoc tribunal to be created to investigate the actions of the accused perpetrators. Six military leaders are named in the report, including Commander-in-Chief Senior General Min Aung Hlaing.

More details of the UN's investigation and recommendations will emerge next month, when a fuller, 400-page report will be published.

Systematic campaign

The report by the UN Independent International Fact-Finding Mission on Myanmar concludes that human rights violations in Kachin, Shan and Rakhine states "undoubtedly amount to the gravest crimes under international law."

In the past, the United Nations has called the alleged campaign of violence, including mass killings, rape and the burning of Rohingya villages by Myanmar government forces a " textbook example of ethnic cleansing ," while UN Special Rapporteur Yanghee Lee has said the attacks bear the "hallmarks of genocide."

The report says the actions of the military compare to previous examples of genocide.

The crime of genocide has never been tried at the International Criminal Court, which was established in 2002 as the world's first permanent war crimes court.

Complicating matters further is that Myanmar is not a member state of the court and the ICC therefore does not have automatic jurisdiction there.

Perpetrators of genocides in the former Yugoslavia and in Rwanda have been convicted through ad hoc tribunals -- the second option suggested in the UN report -- but these have often taken many years to conclude.

Either recommendation in Monday's report is likely to result in a yearslong process, with no guarantee of a conviction.