State Department spokeswoman Elizabeth Trudeau said a U.S. delegation currently holding talks in Myanmar asked the government to “improve transparency” and facilitate a credible independent investigation of the killings.
Trudeau also reiterated a call for humanitarian access.
Rohingya Muslims have fled Myanmar in droves since mid-2012 after communal violence broke out in Rakhine between ethnic Rakhine Buddhists and Rohingya — described by the United Nations as among the most persecuted minority groups worldwide.
The bloodshed is considered the most serious since hundreds were killed in communal clashes in Rakhine in 2012.
For years, members of the minority have been using Thailand as a transit point to enter Muslim Malaysia and beyond.
A law passed in Myanmar in 1982 denied Rohingya — many of whom have lived in Myanmar for generations — citizenship, making them stateless, removing their freedom of movement, access to education and services, and allowing for arbitrary confiscation of property.