Google is closing an engineering centre in Arizona, two years after it opened because the work being done there has been too "fragmented", the company said.

It's a rare move for Google, which is still expanding fairly quickly, if at a slower pace than before. The company added about 450 employees between 31 March and 30 June, for a total of 19,604. It has offices around the globe and is advertising a long list of job openings on its website.

The office in Tempe, Arizona, which has 50 employees, was opened as part of Google's strategy to take advantage of local talent by opening engineering centres across the US. It was supposed to support a variety of Google projects, but that has not worked out as planned, said Alan Eustace, senior vice president of engineering and research at Google, in a blog posting.

"[We’ve found that despite everyone's best efforts, the projects our engineers have been working on in Arizona have been, and remain, highly fragmented," he wrote.

The office will close on 21 November, although Google said the workers won't necessarily be let go. It is working with the employees to "transition them to other locations or to identify other opportunities for them at Google", Eustace wrote.