Two days after Facebook came out with its first major crackdown on ad blocking, popular app AdBlock Plus says the social network's ads can still be wiped out.

On Tuesday, Facebook said it was reworking its software that loads ads so blockers can't remove sponsored posts or videos. Today, AdBlock Plus published a blog calling Facebook's approach a "cat-and-mouse contest" and claimed it has created a piece of code developers and blockers can plug into their software to once again remove Facebook ads.

"Two days ago we broke it to you that Facebook had taken 'the dark path,' and decided to start forcing ad-blocking users to see ads on its desktop site," wrote Ben Williams, communications and operations manager of Eyeo GmbH, maker of AdBlock Plus, in the post. "We promised that the open source community would have a solution very soon, and, frankly, they've beaten even our own expectations."

Williams also acknowledged Facebook could likely tweak its code again to block AdBlock Plus' workaround.

"This sort of back-and-forth battle between the open source ad-blocking community and circumventers has been going on since ad blocking was invented, so it's very possible that Facebook will write some code that will render the filter useless—at any time," he wrote.

For Facebook's part, it claims its tool gives users better control over which ads they see. And like it or not, ads—which users agree to see when visiting the site—are built into the Facebook experience.

"We're disappointed that ad-blocking companies are punishing people on Facebook as these new attempts don't just block ads but also posts from friends and Pages," Facebook said in a statement. "This isn't a good experience for people and we plan to address the issue. Ad blockers are a blunt instrument, which is why we've instead focused on building tools like ad preferences to put control in people's hands."