SAN FRANCISCO (AFP) - Facebook said Wednesday its profit in the past quarter jumped 11 per cent to US$891 million (S$1.2 billion) as advertising revenues soared.

The world's biggest social network also said the number of monthly active users hit 1.55 billion, up 14 per cent from a year earlier.

Revenues leapt 45 per cent from a year ago to US$4.5 billion.

The vast majority was from advertising, and mobile accounted for 78 per cent of ad revenues in the quarter, compared with 66 per cent a year earlier.

"We had a good quarter and got a lot done," said Mark Zuckerberg, Facebook's founder and chief executive.

"We're focused on innovating and investing for the long term to serve our community and connect the entire world."