The European Union slapped Google with a huge 4.34-billion-euro fine for abusing the dominance of its Android operating system in the biggest antitrust penalty in the bloc's history.

EU Competition Commissioner Margrethe Vestager said the US tech giant illegally used Android's near-monopoly to boost usage of its own search engine and browser. The decision, which follows a three-year investigation, comes as fears of a transatlantic trade war mount due to President Donald Trump's decision to impose tariffs on European steel and aluminium exports.