A listing for a live snake was shown on Facebook Marketplace before being reported and taken down. Facebook

Facebook says that a "technical issue" allowed listings for drugs, animals, adult services, and other illegal items to appear in its new Craigslist competitor, Marketplace.

In a statement to Business Insider, Facebook director of product management Mary Ku said the company is "working to fix the problem" and "closely monitoring our systems to ensure we are properly identifying and removing violations before giving more people access to Marketplace."

To police what is sold in Marketplace, a Facebook spokesperson previously told us that the social network will rely on its employees proactively looking for offensive listings as well as users reporting posts they think should be removed.

Facebook has been testing Marketplace with a small percentage of its users for months, but now the feature is replacing the Messenger shortcut in the bottom center of Facebook's app for everyone over the age of 18 in the U.S., U.K., Australia, and New Zealand.

The company originally said on Monday that Marketplace would be available to everyone in those countries within a few days, but now it sounds like the rollout could take longer while Facebook fixes its review process.

Here's Ku's full statement to Business Insider:

“As we expanded Marketplace access, we encountered a technical issue that prevented our reviewing system from identifying some posts that violated our Commerce Policies and Community Standards. As a result, certain posts with content that violated our policies were made visible to people visiting Marketplace. We are working to fix the problem and will be closely monitoring our systems to ensure we are properly identifying and removing violations before giving more people access to Marketplace. We apologize for this issue."