Facebook profits from mobile advertising

Facebook has reported a jump in mobile advertising revenue, easing investor concerns over its future growth.

There have been doubts over Facebook's ability to sell adverts on mobile devices, not least due to their small screen size. Investors had feared that its growth may be hurt as a result.

However, Facebook said 30% of its $1.25bn (£803m) advertising revenue in the first quarter came from mobile.

It reported a net profit of $219m for the January to March quarter.

"We've made a lot of progress in the first few months of the year," said Facebook's founder Mark Zuckerberg.

But increased spending on infrastructure, together with the fact the firm now employs more people than it did a year ago, contributed to a 60% jump in costs and expenses to $1.1bn in the quarter.