Google said Tuesday it had completed its acquisition of Internet ad firm DoubleClick, a move that gives a boost to the Internet search leader in the rapidly growing online advertising sector.

"We are thrilled that our acquisition of DoubleClick has closed," said Google chairman and chief executive Eric Schmidt in a statement hours after European antitrust regulators cleared the deal.

"Google now has the leading display ad platform, which will enable us to rapidly bring to market advances in technology and infrastructure that will dramatically improve the effectiveness, measurability and performance of digital media for publishers, advertisers and agencies, while improving the relevance of advertising for users."

Earlier Tuesday, the European Commission said an investigation opened in November 2007 concluded that the transaction "would be unlikely to have harmful effects on consumers." That followed approval by US regulators last year.

Google ended a bidding war with Microsoft in April 2007 by agreeing to pay 3.1 billion dollars (2.0 billion euros) to add DoubleClick to its Internet money-making arsenal.

The deal had fueled concerns that it could pose privacy risks by giving the Internet giant unprecedented access to personal data.

But regulators on both sides of the Atlantic said they did not take into account the impact on privacy because they are legally required to focus on competition.