The US House of Representatives overwhelmingly adopted a resolution Thursday calling Myanmar's expulsion of hundreds of thousands of Rohingya Muslims a "genocide."
The lower house of Congress also accused the Myanmar military of "crimes against humanity" and called for the immediate release of two Reuters journalists who have been detained for covering the crisis.
The resolution was backed by 394 votes from both parties, with a single Republican opposing.
The United Nations has already classified the mass expulsions of hundreds of thousands of Rohingya from their homes as a "genocide."
Members of Congress called on Secretary of State Mike Pompeo to "determine, based on available evidence, whether the actions by the (Myanmar) military in northern Rakhine State in 2017 constitute crimes against humanity, genocide, or other crimes under international law."
It added that "all those responsible for these crimes against humanity and genocide should be tracked, sanctioned, arrested, prosecuted, and punished under applicable international criminal statutes and conventions."
In November 2017, Pompeo's predecessor Rex Tillerson called the military's campaign against the Rohingya "ethnic cleansing" and in August issued sanctions against four commanders and two military units involved.
Since then, the State Department has been examining whether the actions of the military can be classified as genocide, a tougher, more legally binding term than "ethnic cleansing."
Vice President Mike Pence told Myanmar leader Aung San Suu Kyi last month that the actions of the military were "inexcusable."
"That conclusion of ethnic cleansing... in no way prejudices any potential further analysis on whether mass atrocities have taken place, including genocide or crimes against humanity," State Department deputy spokesman Robert Palladino told reporters this week.
More than 700,000 Rohingya have fled the violence in Rakhine state since the Myanmar military launched an offensive in August 2017.
Myanmar denies the charge of ethnic cleansing, saying it was responding to attacks by Rohingya terrorists.