Lawyers for Meta faced on Tuesday off against the European Commission in the European General Court in Luxembourg over its designation as a “gatekeeper” under the Digital Markets Act (DMA). At issue is the Commission’s ruling classifying Meta’s Messenger and Marketplace apps as core platform services required to comply with DMA rules. Meta contends the apps are extensions of its flagship Facebook platform, which is already covered by the antitrust law, and should not be separately regulated.

The hearing comes just days after Apple filed a separate lawsuit with the General Court, the EU’s second highest tribunal, over the DMA’s interoperability mandate requiring the iPhone-maker to make its sensitive user data available to rivals, compromising the iOS operating system’s privacy and security controls.

 “We design our technology to work seamlessly together, so it can deliver the unique experience our users love and expect from our products,” Apple said in a statement sent to reporters. “The EU’s interoperability requirements threaten that foundation, while creating a process that is unreasonable, costly, and stifles innovation.”

The Meta lawsuit over its gatekeeper designation is separate from a case brought against it over its data processing policies, which resulted in the Commission levying a €228 million ($229 million) fine. The company is considering also appealing the fine.

Meta and Apple are among six tech giants designated as gatekeepers that control significant channels for businesses to reach consumers within the EU, making them subject to the full panoply of regulations under the DMA. Application of the rules, however, is targeted at specific platforms classified as core based on their annual turnover and certain user thresholds.

Related: EU Threatens Apple With Ongoing Fines For Non-Compliance With DMA

Microsoft’s Bing, Edge and Microsoft Advertising, for instance, are not classified as gatekeeper platforms, nor is Apple’s iMessenger. Meta’s Marketplace app was originally covered, but that designation was later withdrawn by the Commission. Meta nonetheless included the designation in its legal challenge to the law.

The legal fights come as the European Commission is taking steps to ease the burden on companies of complying with its complex web of technology regulations, including the DMA, the Digital Services Act (DSA), the GDPR, and the AI Act. In May the Commission released a broad package of measures intended to “simplify” compliance with a wide range of rules across multiple sectors, from energy, to the environment, pharmaceuticals, auto manufacturing, and bio-tech.

The technology regulations, in particular, also have been subject to harsh criticism by the Trump Administration and its allies in Congress, who claim the rules unfairly target American technology companies. Five of the six gatekeeper companies are American, including Microsoft, Amazon, and Alphabet along with Meta and Apple. The sixth company, TikTok-parent ByteDance, is based in China.

In April, the State Department sent letters to the Commission and several European capitals demanding changes to the AI Code of Practice to make it less burdensome for U.S. technology companies. And in May, letters went out criticizing the DSA over what the State Department called a “global censorship-industrial complex,” the Wall Street Journal reported.

Should the Commission lose either of the court challenges to the DMA, or a similar lawsuit filed by TikTok, it could further complicate enforcement of the law. “The commission is already in a very difficult place,” antitrust economist Cristina Caffarra told the Journal. “If the commission loses on this, it is a big loss. That said, I don’t think the DMA is going places anyway.”