Instagram’s new app Threads, which competes with Twitter, has attracted more than 100 million users in less than five days, according to data tracking websites on Monday. This breaks the record of AI tool ChatGPT for the fastest-growing consumer app.

ChatGPT took two months to reach 100 million users, while TikTok took nine months. Instagram itself took two and a half years after its launch in 2010. Threads was released on Apple and Android app stores in 100 countries late on Wednesday, but not in Europe, where Meta, its parent company, is uncertain how to comply with the EU’s data privacy laws. Twitter has about 200 million regular users, but it has faced frequent technical issues since Elon Musk acquired the platform last year and laid off thousands of employees. Musk, who is also the CEO of Tesla and SpaceX, has also lost many users by charging for previously free services and allowing banned right-wing accounts back on the platform.

Many alternatives have emerged, but most of them are niche platforms that lack the ability to grow fast enough to challenge Twitter.

Other websites estimated that the number of Instagram users who downloaded Threads and received “badges” had surpassed the mark earlier. Musk has accused Meta of stealing trade secrets and intellectual property and threatened to sue them, which Meta denies. Meta also owns Facebook and WhatsApp. Musk and Meta’s boss Mark Zuckerberg are rivals, and they recently challenged each other to a cage fight.