NEW YORK, USA — The New York Times cited unnamed sources, including Facebook employees, suggesting that the network had been hiring several smartphone engineers.
Facebook recently admitted it was struggling to make money out of its growing mobile audience.
The company, which recently floated on the stock market, has also just launched its own mobile app store.
The App Center currently offers links to Facebook-enabled apps within Apple's iOS and Google Android stores but developers will soon be able to write apps to be placed exclusively in Facebook's store.
According to the New York Times, Facebook has hired experts who worked on the iPhone and other smartphones.
It quoted a Facebook employee as saying the site's founder Mark Zuckerberg was "worried that if he doesn't create a mobile phone in the near future... Facebook will simply become an app on other mobile platforms".
A Facebook smartphone has reportedly been in the works for some time.
In 2010, Techcrunch reported that Facebook was "secretly" building a smartphone - although this particular project is said to have broken down.
The company's desire to enter the smartphone market could be a result of increasing pressure to improve the potential of mobile to make money.
In a statement for potential investors ahead of its initial public offering earlier this month, the company admitted it had concerns about more users accessing Facebook through their mobile - a trend which could make it more difficult to sell advertising.
When asked by the BBC, a spokeswoman for Facebook said the company did not comment on speculation, and referred instead to a written statement.
"Our mobile strategy is simple: we think every mobile device is better if it is deeply social," the statement read.
"We're working across the entire mobile industry; with operators, hardware manufacturers, OS providers, and application developers to bring powerful social experiences to more people around the world."
Source: BBC News