The AI model Claude has surged in popularity after being blacklisted by the Pentagon last week over ethics concerns.

Claude climbed to the No 1 spot on Apple’s chart of top free apps on Saturday in the US – dethroning OpenAI’s ChatGPT, just one day after the Pentagon tapped OpenAI to supply AI to classified military networks. The bot’s app climbed the iPhone app charts in the UK but did not beat out ChatGPT. Claude also raced up the Android charts in the US and UK, though ChatGPT reigned supreme, according to data from Sensor Tower.

Claude and other apps by the startup Anthropic suffered outages early Monday amid what the company described as “unprecedented demand for Claude” over the last week. More than 1,400 users reported disruptions just after 6am ET, according to Downdetector, an online platform that monitors service outages. By 11am ET, Anthropic stated that the incident was resolved.

Even as the company feuded with the Pentagon, business boomed. “Every single day last week was an all time record for Claude sign-ups,” a statement from the company reads.

Pete Hegseth, the US defense secretary, called Anthropic a supply-chain risk last week, after CEO Dario Amodei refused to back down on red lines around the use of his company’s technology for mass surveillance and fully autonomous weapons. Amodei has said current AI models are not reliable enough to be used in these weapons and that mass surveillance violates constitutional rights. He has also disputed the federal government’s ability to designate Anthropic a supply chain risk, and so far advised customers and Pentagon contractors that their use is unaffected.

The federal government has accused Anthropic of overstepping, with Donald Trump saying on his Truth Social platform: “The Leftwing nut jobs at Anthropic have made a DISASTROUS MISTAKE trying to STRONG-ARM the [Pentagon], and force them to obey their Terms of Service instead of our Constitution.” The Trump administration then tapped OpenAI’s Chat GPT for the job.

Sam Altman, OpenAI’s CEO, announced on Friday that his company struck a deal with the federal government just hours after negotiations between the Pentagon and Anthropic fell through. He said the military would not use ChatGPT for autonomous killing systems or mass surveillance. But those claims have been met with skepticism by many AI experts, lawyers, tech workers and users, who asked why the US government would abandon its partnership with Anthropic, only to strike a deal with OpenAI that has the same safeguards it criticized. Some ChatGPT users, including pop singer Katy Perry, announced their switch to Anthropic on social media and urged others to cancel their subscriptions, too.

Anthropic already had a good start to the year, with free active users increasing by more than 60% and daily signups quadrupling, the company said. Claude’s paid subscribers also more than doubled.

Anthropic has made it easy for new users to make the switch to Claude through its memory feature, which is available on all paid plans. “With one copy-paste, Claude updates its memory and picks up right where you left off,” the company notes on its website. “Claude can import what matters, so your first conversation feels like your hundredth.” A step-by-step guide provides a prompt for the AI provider if a user wishes to leave in favor of Claude.