Big Tech companies are set to face unprecedented restrictions after EU lawmakers on Wednesday backed a package of rules geared at reining in the power of technology giants.

The Digital Markets Act (DMA) will impose strict limits on the behavior of so-called “gatekeeper” platforms, including rules on how they can expand and the obligation to offer customers access to rival services.

The measures, which could still change, target a short list of very large and largely American tech companies including Google, Amazon, Facebook, Apple and Microsoft — a selection that has already angered U.S. officials who accuse Brussels of unfairly taking aim at Silicon Valley firms.

EU lawmakers backed the new rules by a wide majority during a vote in the European Parliament’s Strasbourg site, applauding rules they said could affect the way millions of people use everyday digital products and services.

In practice, the changes are set to limit so-called “killer acquisitions” — when Big Tech firms buy out smaller companies and kill off their innovations — by restricting acquisitions when companies are found to have systematically violated the DMA.

They will also include a new obligation for Big Tech firms to allow users to both uninstall pre-installed apps and provide the option of switching to rival apps.