Washington (CNN) Bipartisan anger about the ongoing violence in Myanmar prompted Trump administration officials Tuesday to defend their approach to the country, where more than 600,000 people have fled persecution.

Hundreds of women, children and men belonging to the Rohingya Muslim minority have been "systematically killed" and driven from their homes, their villages burned to the ground by Myanmar's military, lawmakers charged.

Meanwhile, they complained, the US has made no major change to its ties to Myanmar (also known as Burma), and its officials have shied away from legal terms such as "ethnic cleansing" or "crimes against humanity" despite what many say is strong evidence. The continued violence is undermining Myanmar's fledgling democracy, they warned.

"In recent weeks, we've also witnessed the appalling images of atrocities being committed by the Burmese military against the Rohingya minority ," said Sen. Bob Corker, chairman of the Senate foreign relations committee, at a hearing Tuesday to examine the US policy toward Myanmar. "Hundreds of men and women and children systematically killed. Hundreds of thousands of people fled as their homes burned."

"Time for a policy adjustment"

"The United States should not abandon Burma," Corker said. "However, it may be time for a policy adjustment."

As lawmakers expressed their horror at villages being surrounded and starved, women being raped and children killed, Sen. James Risch, an Idaho Republican, told the witnesses "there is no difference in our feeling, all of the committee. ... We all share this frustration. We all share this outrage."

The foreign relations committee held its hearing as President Donald Trump prepares for his trip to Asia in early November. Democrats noted that while other administration officials have spoken forcefully about the ongoing violence in Myanmar, a country of 54 million that sits between China and India, Trump has been silent.

Now, as pressure increases for Secretary of State Rex Tillerson to use stronger language including the term "ethnic cleansing" some State Department officials argued that they are not simply waiting for a change in terminology to act.

"There have been many questions there about how best to describe the appalling treatment of the Rohingya," Patrick Murphy, the deputy assistant secretary of state for East Asia and Pacific affairs, told reporters Tuesday. "I want to be very clear: We are not shying away from the use of any appropriate terminology. We have a deliberative process to examine facts, and a policy to support the pursuit of additional information to make such determinations."

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Murphy, who had earlier in the day testified about policy towards Myanmar before Corker's committee, was asked by reporters about the State Department's consideration of terms like ethnic cleansing, crimes against humanity or genocide.

"I want to emphasize, we're not waiting for any determination on what best to call it to take actions," Murphy said. "We see that atrocities have been committed, accountability is necessary to both end the violence, ensure that responsibility is taken for actions and acts that have been committed, and to forestall future violence in this complicated part of the country ."

Lawmakers in the House and Senate have proposed a series of new sanctions on Myanmar's military, which, Corker noted, "continues to control key ministries and large swaths of the economy," even after a 2015 election brought the democratic opposition to power and with it, activist Aung San Suu Kyi, who is now the country's de factor leader.

"Shock and dismay"

Suu Kyi's relative silence in the face of the ongoing violence against Rohingya drew criticism from Republicans and Democrats alike.

"Her failure to acknowledge the seemingly systematic campaign of brutality by the Burmese military continues to undermine the civilian government and Burma's democratic transition as a whole," said Corker, describing his "shock and dismay at her dismissiveness" of concerns about what has been happening to Rohingya.

Murphy said that Trump has discussed this situation with other leaders, that Tillerson had spoken by phone with Suu Kyi to urge action on this crisis, that Pence and US Ambassador to the United Nations Nikki Haley had denounced the military's response at the UN, and that the US ambassador in Myanmar has been discussing the violence with government and military leaders.

And Murphy listed a series of possible steps the State Department has taken and could take to hold those responsible for the violence accountable. Those include, among other things, suspending travel waivers for military leaders, considering economic sanctions that could be used to target individuals, and cutting US military aid off to army units involved in operations against the Rohingya.

US officials have pointed out that "these kind of abuses, this kind of displacement," not only threatens the transition to democracy, but it "creates a much bigger risk for the attraction of international terrorism" if the plight of the Rohingya becomes a rallying cry for militant Islamic groups, Murphy said.

Vigilante action

But Murphy's descriptions of the way the violence started clearly angered lawmakers. Murphy said the most recent wave of violence that has sent so many fleeing across the border to Bangladesh was the result of a "disproportionate" response by the military to a Rohingya militant attack. He said that there is also evidence the military has been associated with "vigilante" attacks.

"When I think of vigilante action, I think of sort of rogue individuals not connected with the government doing things," said Sen. Tim Kaine, a Virginia Democrat. "But this is clearly action that isn't just vigilantes, isn't just an expression of sort of endemic prejudice, but there's official actors involved, including the military, in ways that I think are not deniable."

Pushed by Maryland Sen. Ben Cardin, the ranking Democrat on the committee, to say that ethnic cleansing is taking place, Murphy said that he wasn't in a position to make that determination, but that it was under consideration.

"In the meantime, we conclude that there have been atrocities, massive displacement, depopulation of villages that cause us great concern," Murphy said. "We are pursuing all avenues for accountability. Hypothetically, a determination of ethnic cleansing will not change our pursuit of full accountability."