"We are very concerned by the United Nations announcement on September 8 that an estimated 270,000 Rohingya have arrived in Bangladesh since August 25 following allegations of serious human rights abuses in Burma's Rakhine State, including violent attacks and mass burnings of villages," the statement from spokesperson Heather Nauert said.
The State Department is working with international partners, including the Office of the United Nations's refugee agency, the International Committee of the Red Cross and the International Organization for Migration, to provide emergency assistance for the displaced, the statement said.
"Since October 2016, the US government has provided nearly $63 million in humanitarian assistance for vulnerable communities displaced in and from Burma throughout the region," it said.
The statement, like an earlier one by Deputy Assistant Secretary of State for East Asian and Pacific Affairs Patrick Murphy, did not criticize the country's government, however.
The tepid response follows two weeks of sustained violence, triggered by an attack on security forces late last month, which resulted in brutal counterattacks targeting entire villages of Rohingya Muslims. The UN estimates that at least 1,000 people have been killed in the violence, and over a quarter of a million have fled across the border to neighboring Bangladesh.
In a statement Saturday, the insurgent group Arakan Rohingya Salvation Army declared a "temporary cessation of offensive military operations" for a one-month period to enable aid groups to respond to the "humanitarian crisis." The ceasefire would begin on Sunday, the statement said.
In a phone briefing with reporters Friday, Murphy said the US is focused on expanding humanitarian and media access in the region, and condemns a "variety" of attacks -- "attacks on security forces, attacks on civilians (and) attacks by civilians."
"We're very concerned by the sustained allegations of abuses being committed that is resulting of the displacement of many people," Murphy added. "We're urging all parties to take steps to calm tensions."
But Murphy was careful not to directly criticize the country's civilian government, led by Suu Kyi, which he said represents the "best opportunity in generations for Burma to get on the right track" -- referring to the country by its colonial-era name. The government, he added, "inherited a host of enormous challenges."
"Our approach, as a partnership, is to help them build their capacity to have the tools to address the underlying problems," said Murphy.
At the White House, Press Secretary Sarah Huckabee Sanders told reporters President Donald Trump was "aware of the situation and monitoring."
Shortly after, US Ambassador to the United Nations Nikki Haley released a statement saying she welcomed a commitment by Myanmar's government for "humanitarian assistance to all displaced by violence."
"However," she said, "we will continue to urge them to make sure this aid actually reaches those in need, as quickly as possible, and that it is delivered in a manner that protects their rights and dignity."
But leaders in the human rights community have been more pointed in their criticism of Suu Kyi, who was initially silent on the issue, then defended the counterattacks by security forces as an effort to combat terrorism.
Archbishop Emeritus Desmond Tutu, who, like Suu Kyi, is a Nobel Peace Prize recipient, excoriated the leader in a letter posted to his Twitter account
"I am now elderly, decrepit and formally retired," wrote Tutu, "but breaking my vow to remain silent on public affairs out of profound sadness about the plight of the Muslim minority in your country, the Rohingya."
"My dear sister," he goes on to write, "If the political price of your ascension to the highest office in Myanmar is your silence, the price is surely too steep."
Earlier this week, fellow Nobel laureate Malala Yousafzai
also called on Suu Kyi to condemn the violence, writing, "The world is waiting and the Rohingya Muslims are waiting."
State Department officials say they've been in regular contact with Myanmar's government, primarily through US Ambassador Scot Marciel.
In his call with reporters, Murphy called those discussions "productive" and "ongoing," and said the US is finding "very willing partners within the government."
He noted the government's commitment to implementing the recommendations submitted by the Advisory Commission on Rakhine State, led by former UN Secretary-General Kofi Annan.
"It won't be easy," said Murphy. "There are over 80 recommendations, but many of them address the underlying conditions in Rakhine State that cause so much friction and challenge. We want to work with the government, ensure they are focused on this task, have the capacity to address it."