A hacker claims to have breached a law firm used by Trump and dumped legal files on the dark web, report says

• Hackers posted images of documents stolen from a top law firm on the dark web,per The Wall Street Journal.
• The documents marked "confidential" are said to be from law firm Jones Day.
• Donald Trump's administration is among its clients.

Hackers claim to have stolen files from prominent law firm Jones Day and dumped some of them on the dark web, The Wall Street Journal reported.

The newspaper claimed to have reviewed screenshots of some of the files, and said they included a memo to a judge marked "confidential mediation brief," while another is a cover letter for "confidential documents."

The Journal said it was unable to confirm the authenticity of the documents.

Jones Day said on Tuesday that that a file transfer platform it used, Accellion FTA, had been compromised. It said that its own networks had not been breached.

The firm said it was investigating the breach and talking to clients who'd been affected.

In a statement to Bloomberg Law, the firm said: "Jones Day has been informed that Accellion's FTA file transfer platform, which is a platform that Jones Day-like many law firms, companies and organizations-used was recently compromised and information taken."

The hackers denied to the Journal that the files came from Accellion, and insisted they had directly access Jones Day's servers.

The hackers said that they had stolen 100 gigabytes of data, and the Journal found evidence of large files posted on the dark web.

DataBreaches.net first reported Saturday that screenshots of the stolen documents had been posted by hackers who go by the name Clop.

The law firm has several high-profile clients, including former president Donald Trump's administration, as well as his reelection campaign.

There is no information indicating whether files from those accounts are among those that were stolen.