A group of millennial-age technology workers stand near signage for Google at the Googleplex, the Silicon Valley headquarters of search engine and technology company Google Inc, Mountain View, California.

Google is under fire for a new report that describes one of its contracting firms using deceitful tactics while scanning faces of people for the tech giant's data arsenal.

New York's Daily News reported Wednesday that Google contractor Randstand instructed workers to target people, including homeless people, with darker skin by offering $5 gift cards. The report, which cites several sources working on the project, says it is an effort to boost Google's database for its Pixel 4 smartphone, which uses facial recognition biometrics.

In a statement to CNBC, a company spokesperson acknowledged the research project and called diversity "critical" to the Pixel 4's face unlock feature. They also said the company is investigating the claims that Randstand used misleading tactics to persuade people to take part in the facial data gathering project. Randstand did not reply to requests for comment.

"We regularly conduct volunteer research studies," the spokesperson said. "For recent studies involving the collection of face samples for machine learning training, there are two goals. First, we want to build fairness into Pixel 4's face unlock feature. It's critical we have a diverse sample, which is an important part of building an inclusive product. And second, security. Face unlock will be a powerful new security measure, and we want to make sure it protects as wide a range of people as possible."

The report comes two weeks ahead of the company's expected unveiling of its Pixel 4 smartphone. It also comes as the company struggles to retain and attract diverse talent in its ranks, which has affected its ability to detect images of diverse people.

One former employee told the Daily News that Randstad sent a team to Atlanta "specifically" to target black people there while concealing the fact that their faces would be recorded. Randstad reportedly told workers in Los Angeles to go after unsuspecting students on college campuses around the U.S. and attendees of the BET Awards festivities in Los Angeles.

Workers were instructed to lie and rush subjects through the consent agreements or "walk away" if they started to get suspicious, according to the report. One worker said they were told to recite misleading incentives such as, "Just play with the phone for a couple minutes and get a gift card," and, "We have a new app, try it and get $5."

The project's consent agreement stated Google has the right to retain, use or share data without limitation and that data could be processed outside the country, in locations where subjects "may have fewer rights."

"We're taking these claims seriously and investigating them," Google's spokesperson said. "The allegations regarding truthfulness and consent are in violation of our requirements for volunteer research studies and the training that we provided."