2 key groups label Rohingya slaughter 'genocide' as Trump administration stays mum The Trump administration still has not made the determination it is genocide.

Myanmar's violence against the Rohingya, a Muslim-majority ethnic group, constituted a genocide, according to two new reports released Monday -- a determination that the Trump administration still has not made, even after releasing an exhaustive fact-finding report in September that documented the atrocities in horrifying detail.

The administration's silence on genocide is particularly striking because the Public International Law and Policy Group, one of the two groups that made a genocide determination on Monday, worked with the U.S. State Department on the administration's fact-finding report. PILPG reviewed the same evidence that the State Department has and undertook its own legal analysis to reach its conclusion Monday.

But the U.S. has stopped short of using the term genocide, instead saying the slaughter of thousands of Rohingya and displacement of over 700,000 refugees across the border into Bangladesh, is ethnic cleansing.

The U.S. and other countries have agreed to never commit genocide and to take steps to prevent it under the Convention on the Prevention and Punishment of the Crime of Genocide, which defines it as killing, harming or seeking measures to prevent the births or transfer children of a national, ethnic, racial or religious group with intent to destroy them entirely or in part. Ethnic cleansing, which is not defined by international law in the same way, is seen as a lesser charge and defined as expelling one of those groups from that area with violence.

The second report, by the U.S. Holocaust Memorial Museum, warned that the Rohingya that remain in Myanmar are still under threat of genocide, called on the international community to prevent future atrocities and hold those responsible accountable.

The two organizations are now aligned with the United Nations, which concluded in August that the violence was a genocide and recommended a criminal investigation. So far, the U.N. Human Rights Council has established an independent investigative mechanism to collect and analyze evidence, but no Myanmar military officials have been penalized beyond U.S. and European Union sanctions on less than a dozen officials and units.

Myanmar, formerly known as Burma, has denied any wrongdoing, defending its actions as a legitimate counterterror operation and dismissing international outcry as meddling in their domestic affairs.

But the violence has now been widely reported in grisly detail. While the Rohingya have been discriminated against for years -- including by denying them citizenship -- Myanmar has increasingly harassed and detained them since 2012. The military also began to move more security forces into the northern Rakhine state, where the majority of the Rohingya live in the country's northwest.

Then, last August, those forces began a brutal assault on several Rohingya villages that lasted for days. There were mass killings, rapes and gang rapes; mutilations of pregnant women and newborns; burnings and drownings of children; and religious sites, homes and food supplies were destroyed.

"The scale and severity of the attacks and abuses ... suggest that, in the minds of the perpetrators, the goal was not just to expel, but also to exterminate the Rohingya," PILPG found in their new report. "The violence against the Rohingya in northern Rakhine State was well-planned, widespread, systematic, and aimed at terrorizing the Rohingya, rendering them defenseless, and ensuring their removal from Myanmar -- whether by displacement or death."

Based on interviews with 1,024 Rohingya refugees, randomly selected and living in camps in Bangladesh, their report was conducted on behalf of the U.S. State Department, which quietly released the findings in September.

While many had expected a genocide determination to be made then, it did not come. Deputy Secretary of State John Sullivan said at the time, "There weren't legal judgments expressed in it because that wasn't the point of the report," leaving the door open for a determination later.

More than two months later, however, the administration still has not made an announcement on whether the violence amounts to genocide.

But PILPG took the step Monday to release its own legal analysis, finding that the Myanmar military committed genocide, as well as war crimes and crimes against humanity.

"There are reasonable grounds to believe that genocide has been committed because the Rohingya are a protected group for purposes of the law on genocide, and a wide range of prohibited acts underlying genocide were committed against the Rohingya with an intent to destroy, at least in part, the Rohingya as a protected group," according to the analysis.

The State Department did not respond to a request for comment from ABC News, but it has made clear in the past that it stands by its determination of ethnic cleansing.

Paul Williams, the co-founder of PILPG who presented their findings Monday, said the group would not "cross the line into the policy" and comment on the State Department's determination.

"Lawyers, we're never disappointed," he said with a laugh. "We operate in an environment where we're focused on the facts, the law, and then we put it out there, and then the policy shapers, the policy makers pick it up and add in a number of other inputs that we're not qualified to do."

Among those possible "inputs" is the role of China, which has stood by Myanmar as the U.S., Europe and Canada penalized it with sanctions. While Myanmar has longstanding ties to China, the U.S. hoped to bring it into its sphere of influence after its military agreed to hold elections and share power with a civilian government in 2012. Since then, some U.S. officials have urged patience with Myanmar to avoid pushing back into China's orbit.

But calling the military's crimes a genocide could actually pressure the Chinese to do more, according to Naomi Kikoler, the deputy director of the Holocaust Memorial Museum's Simon-Skjodt Center for the Prevention of Genocide.

"The more that we squarely call the crimes for what they are, the more we have to force a conversation about genocide, I think the more difficult it becomes for Chinese to continue to take a position that unfortunately undermines efforts to protect the Rohingya going forward. So I wouldn't dismiss the importance of calling the crimes for what they are from a geopolitical perspective," she told reporters Monday.

The Holocaust Memorial Museum also declined to criticize the administration even though it has not done just that -- call it genocide.

"We have shared our findings with the State Department and have for many years been engaged in dialogue with them," Kikoler said. "Clearly, we are dismayed that the warnings" about the threat to the Rohingya "have gone unheeded by not just the U.S. government, but other governments as well."

Kikoler and Tun Khin, president of Burmese Rohingya Organization U.K., warned that the danger is ongoing for the 500,000 Rohingya that remain in the country and face restrictions on their movements, ability to work, and more.

"Daily, Rohingyas are facing killings and mass atrocities in our country," said Khin. "It is important that U.S. government and others must come with a stronger action and they have -- should come up to say 'genocide.'"

Given that danger, the U.S. and dozens of aid groups have warned that Rohingya refugees living in Bangladesh should not be repatriated to Myanmar despite a Chinese-brokered deal between the two countries to start that process. While the Bangladeshis backed down on the day the first refugees were supposed to be returned, it is unclear whether they have scrapped the plan entirely.

The repatriation plan sparked protests among Rohingya refugees, demanding justice and a safe and voluntary return. Among those left in Rakhine state, several dozen have now tried to escape by boat to Malaysia, only to be caught by Myanmar security forces and returned to camps.