Sony has unexpectedly said its annual loss may be more than four times bigger than initially forecast.

The firm now expects a full-year loss of 230bn yen ($2.15bn; £1.3bn) compared with a previous estimate of 50bn yen.

This was attributed to its struggling mobile business, which has been losing money due to competition from global rivals such as Apple and Samsung.

Sony also said it would not pay a year-end dividend for the first time.

In a statement, Sony said its latest plan had been “modified to address the significant change in the market and competitive environment of the mobile business.”

This is the sixth profit warning from the company, which made the announcement after Japanese stock markets had closed.

Analysts say that while the company faces a hard time returning its smartphone division to profit, it is not impossible.

“They are not the only smartphone vendors to be under a lot pressure,” Rachel Lashford from consultancy Canalys said.

“With the right restructuring and focus on products, at the right prices, it is absolutely possible for vendors to move forward.”

Ms Lashford said both South Korea’s LG and Taiwan’s HTC have seen their smartphone divisions return to profit after several straight quarterly losses.