SAN FRANCISCO (REUTERS) - Facebook reported steady and steep quarterly revenue growth on Wednesday, as the world's largest social network attracted more advertising dollars to its mobile empire, sending its shares to an all-time high.

Facebook, which surpassed two billion active monthly users recently, owns four of the most popular smartphone apps on the planet: its centrepiece Facebook, the photo-sharing Instagram and messaging services Messenger and WhatsApp.

The company's stock rose more than 4 per cent to around US$173 after the stellar earnings report. Up till Wednesday's close, the share price had climbed nearly 44 per cent this year.

With Facebook squeezing more ads into its News Feed, and increasingly into Instagram and the Facebook Messenger service, the company said total revenue rose 44.8 per cent to US$9.32 billion (S$12.65 billion) in the second quarter of the year.

That beat the average forecast of US$9.2 billion among analysts tracked by Thomson Reuters I/B/E/S.

"In mobile, we're continuing to see great strengths," Facebook chief financial officer David Wehner told Reuters. "We're seeing more and more ad dollars getting allocated to mobile, and we think that trend will continue."

Mobile ad revenue accounted for 87 per cent of the firm's total advertising revenue of US$9.16 billion in the latest quarter, up from 84 per cent a year earlier.

"They're killing it on mobile. They are the de facto mobile advertising monopolies, and that's a really big deal," Needham & Co analyst Laura Martin said, adding that she sees no weaknesses in Facebook's business. Facebook and Alphabet own half of the online advertising market worldwide.