Google has been fined €2.95bn (£2.5bn) by the EU for allegedly abusing its power in the ad tech sector - the technology which determines which adverts should be placed online and where.
The European Commission said on Friday the tech giant had breached competition laws by favouring its own products for displaying online ads, to the detriment of rivals.
This decision comes amid increased scrutiny by regulators worldwide over the tech giant's empire in online search and advertising.
Google told the BBC the Commission's decision was wrong and it would appeal.
It imposes an unjustified fine and requires changes that will hurt thousands of European businesses by making it harder for them to make money, said Lee-Anne Mulholland, global head of regulatory affairs at Google.
There's nothing anti-competitive in providing services for ad buyers and sellers, and there are more alternatives to our services than ever before.
US President Donald Trump also attacked the decision, saying in a post on social media it was very unfair and threatening to launch an investigation over European tech practices that could lead to tariffs.
Trump stated: As I have said before, my Administration will NOT allow these discriminatory actions to stand. He further added, The European Union must stop this practice against American Companies, IMMEDIATELY!
This fine represents Google's third significant penalty from the EU, which previously fined the company €4.34bn (£3.9bn) in 2018 for using its Android operating system to establish dominance in that sector.
Teresa Ribera, executive vice president of the Commission, noted that the regulator had considered Google's prior violations when increasing the current fine.
In line with our usual practice, we increased Google's fine since this is the third time Google breaks the rules of the game, she said. Ms Ribera emphasized that Google has 60 days to outline changes to its practices, failing which the Commission could enforce its own solutions.
