U.S. Democratic Senator Dick Durbin called on the Treasury Department to investigate the firm for potential violations of American sanctions on Belarus. Republican Senator Marco Rubio also criticized the company. (Bloomberg)

Talking point: In May, the Waterloo, Ont.-founded firm demonstrated to the Belarus government its ability to block 150 million websites. In August, that technology was used to shut down access to much of the internet during a contentious election. During a call with employees this week, Sandvine executives said they had been working with the government of Belarus for more than a year, and the firm was filtering more than 40 per cent of internet traffic in and out of the country. The firm’s leadership urged staff to keep the information quiet. “We are open to a debate internally on how to improve,” said Alexander Haväng, chief technology officer, on the employee call. “Nobody really feels good about the situation in Belarus.”