Twitter has reported its revenue nearly doubled in the final three months of last year, but user growth fell short of analyst expectations.

"We closed out the year with our business advancing at a great pace," said Twitter chief executive Dick Costolo.

Revenue hit $479m in the fourth quarter, up 97% from $242.6m in the same period a year ago.

Its quarterly loss shrank to $125m, as compared with a $511m loss a year ago.

The number of active monthly users of the San Francisco-based one-to-many messaging service monthly grew to 288 million - just four million more than in the previous quarter.

That figure fell short of expectations - analysts had predicted the figure would climb to 292m.

About 80% of the people using Twitter monthly connected with the service using mobile devices.

Twitter shares were up more than 7% to $44.38 in after-market trades that followed the release of the earnings figures.

Mr Costolo also revealed that "a relationship" with Google has been rekindled, but he was coy on the details.

The deal will make Twitter messages more visible on the Internet, according to reports by Bloomberg News and The New York Times, with tweets showing up in Google searches as soon as they are posted.

"I do want to confirm that we have a relationship that we have agreed to with Google," Costolo said during a quarterly earnings call with analysts.

"I don't have any more details to share with you at this time."

Deutsche Bank analyst Ross Sandler said in a research note this tie-up "could be the catalyst to push shares meaningfully higher," and help Twitter add users.