Google Inc has acquired Angstro, a startup that sorts news and information across social networks like Facebook, a spokesman for the leading Web search provider said on Sunday.

Palo Alto-based Angstro has developed applications to find photos on Facebook, combine Caller ID with LinkedIn profiles and other tools for Twitter, according to the company's website.

The struggle for open, interoperable social networks is still only just beginning, Angstro co-founder Rohit Khare said in a blog post last week.

Google, which runs the top search engine in the United States with more than two-thirds of the market, did not disclose the terms of the agreement.

The Angstro deal underscores the importance to Google of social networks in an increasingly competitive Internet search arena which it dominates.

Last week, Google launched a website for users who want to sift through news, comments and other information on the Internet in real time, letting them follow conversations on social network hubs like Facebook and Twitter in one place.

Microsoft has also announced partnerships with Twitter and Facebook to provide real-time search results.

The buying of Angstro follows acquisitions by Google earlier this year of small startups like Plink, which makes visual search engines, and video broadcaster Episodic.