Google is in discussions to buy micro-blogging site Twitter, according to technology start-up blog TechCrunch.

Citing ‘two people close to the negotiations’ TechCruch owner Michael Arrington reported that Google “is in late stage negotiations to acquire Twitter.”

Later, Arrington updated his entry to say that another source told him talks are at an early stage and could amount to a deal to build a Google real-time search engine.

Writing in TechCrunch, Arrington reported: “We don’t know the price but can assume it’s well, well north of the $250 million valuation that they saw in their recent funding.”

 At the end of last year, Twitter turned down a take over bid from Facebook that valued the company at around half a billion dollars.