Facebook chief Mark Zuckerberg's non-Facebook social media accounts were secure again Monday after being briefly hacked, Facebook said.
Hackers using the name OurMine Team briefly accessed Zuckerberg's accounts on Twitter, Pinterest and LinkedIn on Sunday, according to news reports.
Screen shots posted by tech website Engadget showed a message on Zuckerberg's Twitter feed from OurMine Team, saying "we are just testing your security."
The message was quickly removed from the account.
Facebook denied an earlier report that Zuckerberg's account on its photo network Instagram had also been hacked.
"No Facebook systems or accounts were accessed," a company spokesperson told dpa.
The hack was the second breach of a high-profile Twitter account in a week.
On May 30 the top-ranked account of pop singer Katy Perry, who has 89 million Twitter followers, was targeted by hackers who posted a series of unauthorized messages, including a "miss U baby" to her rival Taylor Swift, US media reported.