Facebook is temporarily banning ads and commerce listings for medical face masks amid growing concern over coronavirus-related exploitation, CNBC reports.

“We’re monitoring COVID19 closely and will make necessary updates to our policies if we see people trying to exploit this public health emergency,” Facebook director of product management Rob Leathern tweeted. “We’ll start rolling out this change in the days ahead.”

The World Health Organization on Tuesday said people have been buying face masks and other equipment leading to a shortage of protective gear for health care workers, putting lives at risk from the new coronavirus and other infectious diseases.”

Facebook earlier announced a ban on ads for medical products which falsely suggest an item is in limited supply, and any that promote fake “cures” or prevention methods for COVID-19. Coronavirus-themed Groups and Pages also will be blocked from its algorithm, Facebook says. The rules apply to Instagram as well. “Supplies are short, prices are up, and we’re against people exploiting this public health emergency,” tweeted Adam Mosseri, the head of Instagram.

Facebook shut down one of its Seattle offices after a contractor there tested positive for novel coronavirus, and asked the company’s 5,000 Seattle-based employees to work from home until March 31st. Facebook has also restricted social visitors to its offices, and canceled its participation in a number of conferences as a result of the outbreak.

EBay and Amazon also have modified their rules around coronavirus-related merchandise. In a notice to sellers Friday, eBay said it was banning all sales of face masks, hand sanitizer, and disinfectant wipes in an effort to stem price gouging. It already has removed more than 20,000 listings for making unverified claims related to coronavirus. Amazon has removed third-party listings that significantly raised prices of hand sanitizer and face masks.