The U.S. and some European governments say Beijing is committing genocide against the Uyghurs, citing a campaign that includes political indoctrination, mass internment and forced sterilizations.

Facebook hasn’t determined whether to act on the concerns, say people familiar with the matter. The company is watching how international organizations such as the United Nations respond to the situation in Xinjiang, one of the people said. The U.N. this week called on firms conducting Xinjiang-linked business to undertake “meaningful human rights due diligence” on their operations.

Beijing has denied any human-rights violations in Xinjiang and contends its actions are necessary to quell terrorist threats in a restive region.

One Facebook employee posted this year in the social-media giant’s internal group for Muslim staff, called Muslim@, to point out that the U.S. government had declared Beijing’s treatment of Uyghurs a genocide, and that Twitter Inc. had taken action against the account of China’s U.S. Embassy for a tweet about Uyghurs that violated its policies.

“It’s time our platform takes action to fight misinformation on the Uighur genocide,” the employee wrote in the post, which was viewed by The Wall Street Journal. The employee described it as a “plea to our leadership.”

A Chinese government spokesman didn’t respond to a request for comment on its Facebook activities or policies in Xinjiang. Beijing has previously denied all allegations of human-rights violations in Xinjiang, instead describing the vast network of camps as vocational training centers aimed at countering terrorism and religious extremism.

While the dollars spent by Beijing are small, Facebook’s deliberations raise the prospect that the company could restrict the government of the world’s most populous country from taking out such advertisements on the platform.

The advertisements and posts by the Chinese government and state media include videos of people in Xinjiang, including some children, proclaiming to the camera that their lives are improving and that Western nations are engaging in a plot to try to destabilize China.

Facebook staff have also internally discussed their unease with what they call Beijing’s misinformation and the potential perception that Facebook is allowing a means for China to spread propaganda relating to humanitarian issues.

Facebook typically removes Beijing’s Xinjiang-related ads within a few days, if internal reviews show they are not properly labeled as pertaining to social and political issues. Advertisers are required, when taking out ads, to indicate in Facebook’s ad-purchasing interface when they cover such topics.

When those rules are followed, ads are then displayed with the name of the entity that paid for them. If not, users see them without that information. China’s Xinjiang-related ads frequently don’t follow Facebook’s rules, but are often viewed tens of thousands or hundreds of thousands of times, and sometimes more, before Facebook removes them.

The Journal on Tuesday reported that Xinjiang-related activity by Chinese state media and diplomats on Facebook and Twitter hit a new high last year, according to new research, as Beijing defended its policies in the region.

Although Facebook has been blocked in China since 2009, its revenue from advertisers in the country may exceed $5 billion a year, according to some research-firm analysts who study digital advertising. That would make it the company’s largest revenue source after the U.S. Facebook doesn’t break out revenue by country.

Taking action against state-controlled media outlets on Facebook presents a quandary for the company, some of those analysts say. The ads may contain content that Facebook staff are uncomfortable with, but introducing policies to tackle them would amount to deciding what governments are allowed to broadcast on the platform.

Government officials and bodies in countries such as Vietnam, Pakistan, Turkey and Saudi Arabia use Facebook to broadcast their views.

China’s state-controlled media outlets run three of the world’s top 20 most-followed Facebook pages, according to online reference library DataReportal. Beijing’s international news channel, CGTN, has more than 115 million followers. That is the fourth-most in the world, surpassing the likes of Coca-Cola and pop star Rihanna.

China’s state-run Xinhua News Agency last month paid less than $100 for an ad promoting a video interview with the mayor of Xinjiang’s capital, Urumqi, in which he says that the “peace and stability that people from all ethnic groups in Xinjiang once longed for has become a reality.” He said a “plot” by Western countries to disrupt China’s internal affairs is “doomed to failure.”

In two days it was shown as many as 200,000 times, according to Facebook advertising data, before it was removed. Xinhua didn’t respond to a request for comment.

“These ads provide a vehicle for Beijing’s propaganda,” said a spokesman for New York-based human-rights group Avaaz, which has studied Xinjiang and the Chinese government’s Facebook advertising practices. “Even if the amounts aren’t huge, it’s a direct profit stream” for Facebook, he said. “That’s what’s particularly troubling.”

CGTN, a part of Chinese state broadcaster CCTV, last year paid more than $400 to promote a video featuring students in a Xinjiang boarding school, where some academic researchers say children of arrested or detained individuals are sometimes sent. In the video, children in interviews say they are happy to be in the facilities because they are eating nutritious food and receiving an education.

The ad was shown more than 1 million times over a four-day period to Facebook users in countries such as Pakistan, India and Bangladesh before it was removed.

Since March 28, CGTN started running at least 10 more ads related to Xinjiang, most of which have been removed.

—Jeff Horwitz contributed to this article.

Write to Newley Purnell at newley.purnell@wsj.com