BRUSSELS: EU antitrust enforcers are set to open a full-scale investigation into Google's $2.1 billion bid for fitness tracker maker Fitbit unless the Alphabet unit offers concessions to address competition concerns, people familiar with the matter said.

The US tech giant could allay such worries by offering a binding pledge along the lines of its promise last year not to use Fitbit's health and wellness data for Google ads, the people said.

The deal allows Google to take on Apple and Samsung in the fitness trackers and smart watches market.