Apple CEO Tim Cook attends an event Nov. 10, 2015, in Milan. Jacopo Raule/Getty Images

SAN FRANCISCO -- In an email sent to all Apple employees, CEO Tim Cook said it was "unacceptable" for three black teenagers to have been barred from entering an Apple Store in Australia. The incident, a video of which went viral earlier this week, was considered the latest example of the tech industry's diversity problem.

In the video, three black teenagers -- reportedly from Sudan and Somalia -- were kept from entering a company store in Melbourne, reportedly due to one employee's fear that "they might steal something." After footage of the interaction appeared online, it spread quickly, and culminated in a message from Apple. "We apologize to the customers involved," the company said.

Cook further addressed the incident in a companywide email, which was obtained by BuzzFeed News and published Friday. Cook said he believes it was an isolated incident, but said the company would use it as an opportunity to retrain leaders at its stores across the world on how to be inclusive with customers of all backgrounds.

"Our stores and our hearts are open to people from all walks of life, regardless of race or religion, gender or sexual orientation, age, disability, income, language or point of view," Cook wrote. "All across our company, being inclusive and embracing our differences makes our products better and our stores stronger."

Though Apple has some of the best diversity figures of any company in the tech industry, its workforce still skews heavily toward white and Asian men. In its latest diversity report, issued in August, Apple showed its global workforce is made up of 31 percent women. Meanwhile, in the U.S., 8 percent of Apple employees are African-Americans and 11 percent are Hispanic.

Cook said an Apple representative personally apologized to the students, a point that had previously been made by Nick Scott, principal of the school the teenagers attend. “All I hoped to do yesterday, and we were very successful in doing this, was to just ask the local Apple Store there to just reassure the boys that they would always be welcome, which they did and they did with good grace,” Scott said, according to the Telegraph.