Twitter shares skidded to all-time lows Thursday after its quarterly update failed to ease concerns that the messaging platform's growth initiatives are sputtering.

At the end of the official trading day on Wall Street, Twitter shares were down 4.47 percent to $14.31, extending their long decline and dropping to the lowest closing price since the social network group went public in 2013.

Shares regained a little ground in after-market trades.

The stock slump came a day after the San Francisco group said its base of monthly active users was 320 million at the end of last year, unchanged from the previous quarter. Excluding those who follow Twitter using text messaging, the user base declined slightly to 305 million from 307 million in the previous quarter.

Twitter, which has never earned a profit, said its loss in the past quarter narrowed to $90.2 million from $125 million a year earlier, but the market was focused more on its user growth.

Mark Mahaney at RBC Capital Markets was among analyst offering a guarded outlook.

"Organic revenue growth is clearly decelerating and all-important user metrics are showing no growth," he said in a note to clients. "We remain cautious, though current aggressive product moves are the right steps."

Blake Harper at Topeka Capital Markets said he had hoped the return of co-founder Jack Dorsey as chief executive could boost growth but that now "it appears it will take more time."

Barclays analyst Paul Vogel noted: "We are encouraged by the pace of innovation following the leadership changes at Twitter over the last six months" but added that "there are still many issues with the service... that keep us on the sidelines."

On the earnings call, Dorsey said Twitter priorities for this year include making it more intuitive to use the service; being a leader in live-streaming video, and making it safer for people to freely express themselves at the platform.

He sought to reassure analysts that he had a system in place to make sure that both companies he runs, Twitter and mobile payments firm Square, get the attention they deserve.

Dorsey declined to detail what other tweaks might be in store for the service, but said there are a "number of broken windows" that needed to be fixed to boost user growth.