Apple, Alphabet’s Google and Meta Platforms face the risk of potentially hefty fines as the European Union opened a full-blown investigation into the firms’ compliance with strict new laws reining in the power of Big Tech.

The European Commission, the 27-nation bloc’s executive arm, said Monday that Apple and Google’s app store rules will be targeted in the first probes under the bloc’s Digital Markets Act (DMA), how Google search results might unfairly preference its own services and how Apple may make it harder for users to choose alternatives to its Safari browser, Bloomberg reported.

New subscription fees for Meta’s Instagram and Facebook platforms will also be targeted by the probe, which could hit firms with fines of up to 10 percent of global revenue, or up to 20 percent in the case of repeated breaches. “We suspect that the suggested solutions put forward by the three companies do not fully comply with the DMA,” EU antitrust chief Margrethe Vestager said. She added that the probes involve “serious cases.”

The commission also warned about further scrutiny on Apple’s new fee structure for alternative app stores and Amazon.com’s ranking practices on its marketplace. The DMA that took full effect earlier this month is a broad rulebook that targets Big Tech “gatekeeper” companies providing “core platform services.”

An Apple spokesperson said the company is confident it complies with the DMA, while Google’s director for competition, Oliver Bethell, said the firm has made significant changes to its services in Europe and that it will “continue to defend our approach in the coming months.” Meta said it designed its offerings to comply with various regulatory obligations, including DMA.

For Apple, the EU probe comes as a one-two punch with a sweeping antitrust probe in the US, accusing the iPhone maker of violating antitrust laws by blocking rivals from accessing hardware and software features on its popular devices. The EU also recently hit Apple with a ₹1.8 billion ($2 billion) fine for blocking music streaming apps from informing users of cheaper deals.