The US Federal Trade Commission is “preparing a recommendation” that the US government sues Google, following an investigation that has probed its activities including its mobile business, the New York Times reports.

While the centrepiece of the case is Google’s core search business, the report also said that the authorities are exploring Google’s smartphone activities, including whether contracts with handset makers and operators prevent them from removing or modifying Google products.

In addition, Google’s use of its mobile patent portfolio is also in the spotlight – a holding it bolstered through its acquisition of Motorola Mobility earlier this year.

According to the New York Times, the US authorities are undertaking “the most far-reaching antitrust investigation of a corporation since the landmark federal case against Microsoft in the late 1990s”.

The core focus is on whether Google manipulates its search results so its own products and services appear first, making it more difficult for rivals to compete.

It was noted that the FTC’s action does not mean the government will sue Google: a vote of the FTC commissioners is the next step.

And it was suggested that as the case progresses, “each step is a further prod for Google to make concessions to reach a settlement before going to court”.