The evidence shows "a clear intent behind these mass atrocities - the intent to destroy Rohingya, in whole or in part," Blinken said.
US Secretary of State Antony Blinken has formally declared that the Myanmar military's attacks on the Rohingya in 2016 and 2017 was "genocide", saying there was "clear intent" to destroy the Muslim minority.
"I have determined that members of the Burmese military committed genocide and crimes against humanity against Rohingya," Blinken said on Monday.
The evidence shows "a clear intent behind these mass atrocities - the intent to destroy Rohingya, in whole or in part," he said at the US Holocaust Memorial Museum.
At least one member of Congress, Democratic Sen. Jeff Merkley of Oregon, welcomed the anticipated step.
“I applaud the Biden administration for finally recognising the atrocities committed against the Rohingya as genocide," he said in a statement.
“While this determination is long overdue, it is nevertheless a powerful and critically important step in holding this brutal regime to account," Merkley said.
Merkley called on the administration to continue the pressure campaign on Myanmar by imposing additional sanctions on the government to include its oil and gas sectors.
Additional international pressure
The designation does not in and of itself portend drastic new measures against Myanmar’s military-led government, which has already been hit with multiple layers of US sanctions since the campaign against the Rohingya ethnic minority began in the country's western Rakhine state in 2017.
But it could lead to additional international pressure on the government, which is already facing accusations of genocide at the International Court of Justice in The Hague.
Human rights groups and lawmakers have been pressing both the Trump and Biden administrations to make the designation.
More than 700,000 Rohingya Muslims have fled from Buddhist-majority Myanmar to refugee camps in Bangladesh since August 2017, when the Myanmar military launched a clearance operation in response to attacks by a rebel group.
Myanmar security forces have been accused of mass rapes, killings and the burning of thousands of homes.