San Francisco police say they’ve arrested a suspect who allegedly attacked the home of OpenAI CEO Sam Altman and then made threats outside the company’s headquarters.

At around 3:43 am on Friday, officers responded to a report of a person throwing an incendiary weapon at the home of a CEO, San Francisco Chronicle reported, which was later identified as Altman’s. A suspect, whose identity has not been released, was later arrested. No one was hurt.

OpenAI’s security team alerted employees about the apparent attack, Wired reported.

“At approximately 3:45 am PT, an unidentified individual approached Sam’s residence and threw an incendiary device toward the property,” the security team’s note to staff reads. “The device landed nearby and extinguished. There were no injuries and only minimal damage was reported.”

“Shortly afterward, an individual matching the suspect’s description was contacted by security outside MB1,” it continues, referring to the company’s HQ in the Mission Bay neighborhood. “This person made threatening statements about the building.”

In a statement to Wired, an OpenAI spokesperson described the incendiary weapon as a Molotov cocktail.

“Early this morning, someone threw a Molotov cocktail at Sam Altman’s home and also made threats at our San Francisco headquarters. Thankfully, no one was hurt,” the spokesperson said. “We deeply appreciate how quickly SFPD responded and the support from the city in helping keep our employees safe. The individual is in custody, and we’re assisting law enforcement with their investigation.”

Security are keeping on their toes. Though the headquarters remains open, the security team informed staff that employees may notice an increased police and security presence around the building on Friday, and employees were cautioned to “not let anyone tailgate into the building,” per Wired.

The alleged attack comes after heightened backlash against OpenAI for Altman’s agreement with the Department of Defense to deploy its AI systems across the military. The company has periodically faced protests outside its headquarters, including one last month. In November, its San Francisco office went on lockdown after it allegedly received a violent threat from an activist.

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