European Parliament members asked Mark Zuckerberg today whether Facebook was a monopoly that potentially needed breaking up, echoing concerns voiced in the United States. In a conference with Zuckerberg, German MEP Manfred Weber asked whether the Facebook CEO could name a single European alternative to his “empire,” which includes apps like WhatsApp and Instagram in addition to Facebook. “I think it’s time to discuss breaking up Facebook’s monopoly, because it’s already too much power in only one hand,” said Weber. “So I ask you simply, and that is my final question: can you convince me not to do so?”

The question was later picked up by Belgian MEP Guy Verhofstadt. “You cannot convince him, because it’s nonsense actually,” said Verhofstadt. “You have given the example of Twitter, you have given the example, I think, of Google as some of your competitors. But it’s like somebody who has a monopoly in making cars is saying ‘Look, I have a monopoly in making cars, but it is no problem. You can take a plane, you can take a train, you can even take your bike!’” He asked whether Facebook would cooperate with European antitrust authorities to determine whether the company was indeed a monopoly, and if it was, whether Facebook would accept splitting off WhatsApp or Messenger to remedy the problem.

The panel’s format let Zuckerberg selectively reply to questions at the end of the session, and he didn’t address Verhofstadt’s points. Instead, he broadly outlined how Facebook views “competition” in various spaces. “We exist in a very competitive space where people use a lot of different tools for communication,” said Zuckerberg. “From where I sit, it feels like there are new competitors coming up every day” in the messaging and social networking space. He also said that Facebook didn’t hold an advertising monopoly because it only controlled 6 percent of the global advertising market. (It’s worth noting: this is still a huge number.) And he argued that Facebook promoted competition by making it easier for small businesses to reach larger audiences — which is basically unrelated to the question of whether Facebook itself is a monopoly.

As Weber noted, antitrust questions came up in Zuckerberg’s earlier US congressional hearings. A coalition of activists also just launched a “Freedom from Facebook” campaign that urges the US Federal Trade Commission to split up Facebook, WhatsApp, Instagram, and Facebook Messenger. So while many people left today’s meeting with their questions unanswered, the monopoly issue isn’t going away.