Facebook boss Mark Zuckerberg has strongly denied the social network is planning to release its own phone. In an effort to dispel long-running rumours, Mr Zuckerberg said releasing a Facebook phone was "not the right strategy".

"We have more engagements from the people who we reach, and I think we'll also be able to make more money for each minute people spend with us on their mobile devices” he said.

His comments came as his company announced a sharp drop in profits - but an increase in revenue. The company made a profit of $64m in the final three months of last year, compared with $302m a year earlier. But it has seen an increase in revenue coming from mobile advertising - an area investors see as one of the company's biggest challenges.