US Secretary of State Rex Tillerson speaks during a joint press conference with Myanmar Foreign Minister Aung San Suu Kyi at the Foreign Ministry office in Naypyitaw, Myanmar, Wednesday, Nov. 15, 2017.

:: US Secretary of State Rex Tillerson said Wednesday that his country was deeply concerned by “credible reports” of atrocities committed by Myanmar’s security forces and called for an independent investigation into a humanitarian crisis that has seen hundreds of thousands of Muslim Rohingya flee to Bangladesh.

Speaking at a joint news conference with leader Aung San Suu Kyi in Myanmar’s capital, Tillerson said the US would consider individual sanctions against people found responsible for the violence, but he would not advise “broad-based economic sanctions” against the entire country.

“All of that has to be evidence based,” Tillerson said. “If we have credible information that we believe to be very reliable that certain individuals were responsible for certain acts that we find unacceptable, then targeted sanctions on individuals very well may be appropriate,” he said.

Tillerson’s one-day visit comes as a new report said there was “mounting evidence” of genocide against the Rohingya in Myanmar’s northern Rakhine state, where a government security operation has caused more than 600,000 Rohingya to flee to neighboring Bangladesh.

Tillerson also met with Myanmar’s powerful military chief, Min Aung Hlaing, who is in charge of operations in Rakhine.

A senior US State Department official said Tuesday that Tillerson would use the visit to “express concerns over the displacement and violence and insecurity affecting Rohingya populations and other local populations and discuss ways to help Burma stakeholders implement commitments aimed at ending the crisis and charting productive ways forward.”

Myanmar was formerly known as Burma.

Though Suu Kyi has been the de facto head of Myanmar’s civilian government since her party swept elections in 2015, she is limited in her control of the country by a constitution written by the military junta that ruled Myanmar for decades. The military is in charge of the operations in northern Rakhine, and ending them is not up to Suu Kyi.

Still Suu Kyi has faced widespread criticism for not speaking out in defense of the Rohingya. At Wednesday’s news conference Suu Kyi denied she had been silent on the issue, saying she had personally commented on the situation as well as issued statements through her office.

“I haven’t been silent,” she said. “What people mean is what I say is not interesting enough. But what I say is not meant to be exciting. It’s meant to be accurate. And it’s aimed at creating more harmony and a better future for everybody. Not setting people against each other.”

The report by the United States Holocaust Memorial Museum and the advocacy group Fortify Rights found there is “mounting evidence” of genocide against the Rohinyga. It accused security forces and civilians of mass killings — including burning victims alive including infants — rape and other abuses, and called on the international community to take action.

“These crimes thrive on impunity and inaction,” said Matthew Smith, the head of Fortify Rights. “Condemnations aren’t enough. Without urgent international action towards accountability, more mass killings are likely.”

Myanmar’s military has denied the accusations, most recently with a statement Monday. The military said it had interviewed thousands of people during a monthlong investigation into the conduct of troops in Rakhine after Rohingya insurgents launched a series of deadly attacks there on Aug. 25.

While the report acknowledged that battles against militants from the Arakan Rohingya Salvation Army had left 376 “terrorists” dead, it also claimed security forces had “never shot at the innocent Bengalis” and “there was no death of innocent people.”

Myanmar’s government and most of the Buddhist majority say the members of the Muslim minority are “Bengalis” who migrated illegally from Bangladesh and do not acknowledge the Rohingya as a local ethnic group even though they have lived in Myanmar for generations.