The Department of Justice said measures may include "structural requirements" to prevent Google from maintaining its search engine's "monopoly", something the company warned could very well have unintended consequences for American businesses and consumers.

The DoJ was expected to submit a more detailed set of proposals by 20 November, while Google will have until 20 December to submit its own proposed remedies.

As of 0850 BST, shares in Google parent company Alphabet were down 0.072% in pre-market trading at $165.70 each.

Reporting by Iain Gilbert at Sharecast.com