More than two dozen state attorneys general urged major e-commerce companies on Wednesday to do more to combat price gouging, as online sellers jack up prices during the coronavirus pandemic.

Led by Pennsylvania Attorney General Josh Shapiro, 33 attorneys general called on the companies to set and enforce polices restricting unreasonable price increases during emergencies, as well as trigger protections when price gouging occurs and create pages where consumers can file complaints.

“Ripping off consumers by jacking up prices in the middle of a public emergency is against the law, and online resellers like Amazon must join in this fight,” Shapiro said in a statement. “These companies form the backbone of online retail and have an obligation to stop illegal price gouging now and put strong practices into place to stop it from happening in the future.”

The letters from the attorneys general, sent to Amazon, Craigslist, eBay, Facebook, and Walmart, cite a report from the U.S. Public Interest Research Group Education Fund, which found examples of prices rising at least 50% for some hand sanitizers and face masks. In one case on Craigslist, a two-liter bottle of hand sanitizer cost $250 — 10 times the regular price.

In a blog post, Amazon said it’s monitoring for price gouging, removing bad actors, and collaborating with law enforcement to hold price gougers accountable. In a statement, eBay said it is “making every effort to ensure that anyone who sells on our platform follows local laws and eBay policies.” Walmart recently told attorneys general that it removes items offered by third-party sellers if they’re priced substantially higher.

“Facebook is focused on preventing exploitation of this crisis for financial gain,” company spokesperson Daniel Roberts said. “While enforcement is not perfect, we have put several automated detection mechanisms in place to block or remove this material from our platform.”

Craigslist did not return a request for comment.

The U.S. PIRG Education Fund found that existing monitoring on Amazon’s platform didn’t stop significant price hikes. The group analyzed prices on dozens of items featured in searches for “surgical masks,” “surgical masks antiviral disposable,” and “hand sanitizer." The analysis found that the cost of these products would at times spike 2.3 times higher than the 90-day average.

“Americans are already worried about their health and the health of their loved ones during this pandemic," Adam Garber, the U.S. PIRG Education Fund Consumer Watchdog, said in a statement. “They shouldn’t also have to worry about being ripped off on the critical supplies they need to get through it.”