In the face of widespread "atrocities" against ethnic Rohingya people in Myanmar, the United States has been cautiously stepping up pressure on that country's army, while taking care to avoid endangering the civilian government of Aung San Suu Kyi.
As the US takes a more active role in the region — several American delegations have passed through in recent weeks — secretary of state Rex Tillerson plans to travel to Myanmar on Wednesday to meet Ms Suu Kyi, the nation's leader, as well as army chief Gen Min Aung Hlaing.
Myanmar is the country formerly known as Burma.
Mr Tillerson is expected to adopt a firm tone with military leaders there, whom he has deemed "responsible" for the crisis facing the Rohingya, an embattled Muslim minority that has seen more than 600,000 of its members flee to neighbouring Bangladesh in two and a half months.
In the name of putting down a supposed Rohingya rebellion, the army has since late August waged a sweeping military campaign in the western state of Rakhine, burning villages and sending thousands into what has become the largest exodus in today's world.
The United Nations has denounced the campaign, including allegations of killings and mass rape, as "ethnic cleansing".
'Shocking' scenes
Recently returned from Myanmar and the overflowing refugee camps in Bangladesh, Simon Henshaw, the State Department official responsible for refugee and migration issues, said the scene in the camps was "shocking".
"The scale of the refugee crisis is immense," he said, adding: "The conditions are tough. People are suffering."
"Many refugees told us, through tears, accounts of seeing their villages burnt, their relatives killed in front of them," Mr Henshaw said.
"The world can't just stand by and be witness to the atrocities that are being reported in that area," Mr Tillerson said last month.
But it is unclear what steps the United States might take. Up to now, the State Department has merely strengthened a few punitive measures aimed at Myanmar's army.
'Little concrete action'
The initial condemnations were "important", Sarah Margon of the organisation Human Rights Watch told AFP, "but they stopped and there has been very little concrete action since then".
She called for targeted economic sanctions meant to bring an end to "some of the most brutal and horrific atrocities that have been seen in years".
In the absence of more determined action from the White House or State Department, several members of the US Congress are calling for sanctions to limit military co-operation with Myanmar and ban its army members from US soil. A draft bill would also ban the importation of rubies or jade from the country.
"The bill is an important, although belated, first step in pushing the Myanmar military to end the violence in Rakhine state," said Joshua Kurlantzick of the New York-based Council on Foreign Relations. Now, he said, other parts of the government "should take action as well".
The State Department has not ruled out supporting further sanctions.
But the United States has been careful not to place blame on Aung San Suu Kyi, drawing a line between the military and the civilian government led by the Nobel Peace Prize laureate.
While Ms Suu Kyi has faced considerable criticism abroad for her apparent lack of empathy for the Rohingya, Washington has reaffirmed its support for her, saluting her commitment to allow the peaceful return of refugees.
A swipe at Suu Kyi
The US ambassador to the United Nations, Nikki Haley, did however take a side swipe at Ms Suu Kyi, saying the situation in her country "should shame senior Burmese leaders who have sacrificed so much for an open, democratic Burma".
The United States wants to support "the transition to a civilian government [but] make sure there's no backsliding", said a senior State Department official, speaking on background while emphasising that Ms Suu Kyi, once a dissident, has to deal with an army that ruled unchallenged for nearly a half-century.
And new sanctions could be taken badly in Myanmar, said historian Thant Myint-U. In the past, he told AFP, sanctions "made any transition to democracy less likely to succeed, and entrenched the isolation that is at the heart of all of Burma's problems".
Ms Margon of Human Rights Watch acknowledged that Myanmar is in "really a difficult, delicate balance", and added that the civilian government had been "very disappointing" in its handling of the refugee crisis.
Still, she added, "they are not the ones committing the atrocities, they are not the ones responsible for the ethnic cleansing."
But Ms Margon and, separately, Mr Kurlantzick said the United States could privately deliver a stern message to Ms Suu Kyi on the urgent need to do more.
Mr Kurlantzick said Mr Tillerson should warn the country's generals that tougher multinational sanctions could ensue unless the violence stops, even while he cautions civilian leaders that they "are not necessarily exempt" from new sanctions.