The violence which drove 700,000 Rohingya Muslims from Myanmar into Bangladesh was "without excuse", US Vice President Mike Pence told Aung San Suu Kyi in stinging comments on Wednesday.
Suu Kyi has seen her reputation as a rights defender shredded by her refusal to speak up for the Rohingya, a stateless group reviled in the Buddhist-majority country.
She has already had an Amnesty International honour revoked this week and faced sharp words from Malaysia's prime minister at a usually tepid meeting of Southeast Asian nations in Singapore.
In direct remarks as he sat next to Suu Kyi, Pence condemned the "violence and persecution" against the Rohingya as "without excuse".
Then in a front-on challenge to Myanmar's civilian leader, Pence said he was "anxious to hear about the progress" being made to hold the perpetrators accountable.
A crackdown led by Myanmar's army last year sparked an exodus of the Muslim minority into neighbouring Bangladesh.
UN investigators say the army's actions amounted to genocide.
Suu Kyi brushed off Pence's comments.
"In a way, we can say we understand our country better than any other country does," she said.