Facebook founder Mark Zuckerberg has said his new social media app, Threads, is attracting more users than he expected.

The app attracted more than 100 million signups within days of its launch this month in a challenge to Elon Musk’s rival platform X, formerly Twitter.

But analysts questioned whether Threads would be able to keep people engaged.

External data firms have reported that registrations and time spent on the platform have declined since launch.

Zuckerberg said the initial success had surprised executives and “we’re seeing more people coming back every day than I expected.”

He said that improving this engagement was the focus of the company now and success was not a “fore-gone”.

“We have a lot of work to do to make Threads reach its full potential,” he said.

His remarks came as Meta, the parent company of Facebook, Instagram and WhatsApp, reported rising ad sales and steady user growth, with 3.07 billion people globally active on one of its apps every day.

The earnings suggest Meta is emerging from last year’s slump, when ad sales fell in the face of increased competition, Apple’s privacy changes and general economic weakness.

Meta said it hit $32 billion in ad sales in the April-June period, up 11% from a year earlier. That was better than analysts expected, with growth accelerating from the previous quarter. Profits rose even faster, rising 16% year over year to $7.79 billion.

The results helped lift the firm’s shares in after-hours trading. The share price has already more than doubled since the start of the year as investors embrace Zuckerberg’s campaign to cut costs and refocus the tech giant.

Meta said it employed about 71,469 people at the end of June, down 14% from a year ago. He said the figure only reflected the impact of about half a thousand layoffs he has announced in recent months.

“There’s a lot to feel good about when it comes to Meta right now,” said Insider Intelligence principal analyst Debra Aho Williamson.

She said the company still had to navigate a weak advertising market and stiff competition in advertising and artificial intelligence. Its investments in virtual reality have also yet to pay off.

“These things will weigh on Meta in the second half of the year, but thanks to the moment… it will be in a stronger position to face these challenges,” she said.