The EU turned the screw on US tech giants Wednesday, ordering Amazon to repay Luxembourg 250 million euros in back taxes and referring Ireland to the top EU court for failing to collect billions from Apple.

Europe’s competition chief Margrethe Vestager accused tiny Luxembourg of an illegal deal with internet shopping giant Amazon to pay less tax than other businesses.

The two cases are part of a wider offensive by the EU on Silicon Valley behemoths as Europe seeks ways to regulate them more tightly on issues ranging from privacy to taxation.

“Luxembourg gave illegal tax benefits to Amazon. As a result, almost three quarters of Amazon’s profits were not taxed,” Vestager said in a statement.

The tax demand comes a year after the hard-charging Vestager ordered tech icon Apple to repay 13 billion euros ($14.5 billion) in back-taxes to Ireland in a decision that shocked the world.

In a sign that it was not letting up, the EU on Wednesday referred Ireland to the EU’s highest court for failing to collect the bill. “The European Commission has decided to refer Ireland to the European Court of Justice for failing to recover from Apple illegal state aid,” the EU’s anti-trust regulator said in a statement.