Facebook is firing back at a report claiming it enables companies to violate federal employment discrimination law by letting them place recruitment ads on the social network targeted at people younger than 40.

ProPublica on Wednesday reported that "dozens of the nation's leading employers — including Amazon, Goldman Sachs, Target and Facebook itself" have placed recruitment ads on Facebook that are "limited to particular age groups." This practice, according to the NYC-based investigative journalism nonprofit, may violate the federal Age Discrimination in Employment Act of 1967, which protects job applications and employees 40 years-old or older from discrimination on the basis of age.

ProPublica quoted one employment lawyer, Debra Katz, who said the practice is "blatantly unlawful."

In a Thursday blog post, however, Facebook pushed back on the claim that this practice violates the law.

"Simply showing certain job ads to different age groups on services like Facebook or Google may not in itself be discriminatory — just as it can be OK to run employment ads in magazines and on TV shows targeted at younger or older people," Facebook's Vice President of Ads Rob Goldman wrote. "What matters is that marketing is broadly based and inclusive, not simply focused on a particular age group."

The controversy comes after ProPublica in October 2016 revealed that Facebook let advertisers narrow their audience by "ethnic affinity," or, in other words, exclude people who are African-American, Asian, or Hispanic. Facebook, in response to that report, promised to roll out tools to detect and automatically disable "ethnic affinity" marketing.

This time around, Facebook says it disagrees with ProPublica.

"Used responsibly, age-based targeting for employment purposes is an accepted industry practice and for good reason: it helps employers recruit and people of all ages find work," Goldman wrote.