Google says the US Justice Department has asked for more information about its bid for Motorola Mobility but expressed confidence the US$12.5 billion deal will get the green light.
"We know that close scrutiny is part of the process and we've been talking to the US Department of Justice over the past few weeks," Google senior vice president Dennis Woodside said in a blog post.
"Today we received what is called a 'second request,' which means that the DoJ is asking for more information so that they can continue to review the deal," Woodside said, adding that such a request was "pretty routine."
"While this means we won't be closing right away, we're confident that the DoJ will conclude that the rapidly growing mobile ecosystem will remain highly competitive after this deal closes," he said.
"We believe very strongly this is a pro-competitive transaction that is good for Motorola Mobility, good for consumers, and good for our partners," Woodside said.
"We'll be working closely and cooperatively with (the DoJ) as they continue their review," he added.
The boards of directors of Google and Motorola Mobility have unanimously approved the deal - Google's largest acquisition ever, dwarfing its $3.1 billion purchase of online advertising firm DoubleClick.
Google's acquisition of Motorola Mobility will also require regulatory approvals from the European Union.
The US Federal Trade Commission is presently conducting a probe into Google's internet search and advertising business and past Google acquisitions have come in for close scrutiny from US and European regulators.