US Secretary of State Rex Tillerson on Thursday condemned violence against Rohingya Muslims in Myanmar as "unacceptable", as thousands of refugees continue to stream across the border into Bangladesh.
"We need to support Aung San Suu Kyi and her leadership but also be very clear and unequivocal to the military power sharing in that government that this is unacceptable," Tillerson said.
"This violence must stop. This persecution must stop. It has been characterised by many as ethnic cleansing. That must stop," he said during a visit to London, speaking alongside British counterpart Boris Johnson.
"I think it is a defining moment in many ways for this new emerging democracy," Tillerson said, acknowledging that Myanmar's leader Suu Kyi found herself in a "difficult and complex situation".
A crackdown by Myanmar's army, launched in response to attacks by Rohingya militants on August 25, has pushed vast numbers of refugees from the stateless Muslim minority across the border.
Some 389,000 are estimated to have crossed since then.