At least two US senators intend to probe Clearview AI, the secretive facial recognition startup that’s compiled a database of billions of photos scraped from Facebook, Instagram, and other websites, about the sale of its technology to countries with documented human rights abuses.

On Tuesday, Democratic Sen. Ed Markey of Massachusetts sent a letter to the company questioning the sharing of its facial recognition software with countries including Saudi Arabia and the United Arab Emirates, following reporting from BuzzFeed News. Last week BuzzFeed News reported that Clearview documents indicate that more than 2,200 private and public organizations around the world, including the FBI, Macy’s, and law enforcement agencies in 27 different counties, have tried its technology, which matches a photo of someone’s face to existing pictures of them on the web.

Markey, who also sent a letter to Clearview in January following stories in the New York Times and BuzzFeed News, called responses to that initial inquiry “unacceptable.” He sent a second letter on Tuesday, noting that the company is unique from other facial recognition firms because “it scrapes billions of photos from social media sites rather than using relatively limited sets of photos from existing government databases.”

“Recent reports about Clearview potentially selling its technology to authoritarian regimes raise a number of concerns because you would risk enabling foreign governments to conduct mass surveillance and suppress their citizens,” he wrote.

Markey’s letter comes on a day when a representative for Clearview is also expected to meet with Sen. Ron Wyden’s office to discuss the use of its technology and its rapid expansion. A spokesperson for Wyden’s office said that Clearview CEO Hoan Ton-That had been expected to attend but pulled out the night before. This is the third time the executive has asked to reschedule.

A Clearview spokesperson did not immediately respond to questions about Markey’s letters or the company’s meeting with Wyden’s office.

Since unveiling some of the details around its facial recognition software earlier this year, Clearview AI has drawn scrutiny for its claims about the accuracy of its technology and the entities with which it works. While Ton-That has maintained in media interviews that his company is focused on working with law enforcement agencies in the US and Canada, BuzzFeed News’ reporting last week showed the company is looking to expand in sectors including retail, real estate, and banking, and markets from Brazil to the Middle East.

Of particular interest to Markey and Wyden is Clearview’s work in Saudi Arabia and the UAE. According to company documents reviewed by BuzzFeed News, the startup had provided free trials to various government-related agencies there. Those same documents showed that UAE’s sovereign wealth fund, Mubadala Investment Company, had run searches using the facial recognition tech, as had the Ministry of Interior’s Child Protection Center in Abu Dhabi.

In Saudi Arabia, Clearview documents show the company gave access to the Thakaa Center, also known as the AI Center of Advanced Studies, a Riyadh-based research center whose clients include Saudi Arabia’s Ministry of Investment. News outlets have documented numerous human rights violations in the UAE and Saudi Arabia, where, for example, there are laws that discriminate against LGBTQ individuals.

In a Jan. 31 letter written in reply to an early inquiry from Markey, Clearview lawyer Tor Ekeland made no mention of the company’s private industry or international clients, describing its software as a “critical law enforcement tool.” In the letter, Ekeland noted that Clearview had not been aware of any abuses of the tool and noted that “all the harm is speculative.”

“Clearview is committed to keeping it that way, and working with you to ensure that the use of biometrics in law enforcement strikes the proper balance between protecting our communities and our constitutional rights,” he wrote.

On Tuesday, Markey called that four-paragraph letter from Clearview “unacceptable” and sent another inquiry. In it, he asked if the company could guarantee that its technology would not enable human rights abuses and inquired about what steps, if any, had been taken to ensure that Clearview was in compliance with the Children’s Online Privacy Protection Act (COPPA).

He also asked a question about the company’s plans to work on live facial recognition with surveillance cameras and augmented reality glasses. “If so, will Clearview commit to halting all such integration given the grave privacy and civil liberty risks this would pose to the public?” he asked.