European Commissioner for Competition Margrethe Vestager talks to the media during a news conference on the concurrence case with Google online search advertising on March 20, 2019 in Brussels, Belgium.

Europe's top competition authority will look into smaller acquisitions made by big technology giants after a "shopping spree" in recent years by American firms, as regulators in the region look to ramp up pressure on major U.S. players.

The continent has been a hot bed of technology acquisitions by major U.S. firms over the last decade, particularly in the area of artificial intelligence.

High-profile purchases like the $8.5 billion Microsoft paid for Skype in 2011 or the $19 billion Facebook bought WhatsApp for in 2014 often make the headlines, but there are dozens of other smaller acquisitions that have happened.

Last year for example, Apple bought Spectral Edge for an undisclosed sum. It's a U.K.-based start-up working on photography technology. Twitter meanwhile acquired Fabula AI, another U.K.-based artificial intelligence firm. There are many more examples like this involving other technology giants such as Alphabet and Facebook.