The Guardian says it was warned of cyber attacks by Saudi Arabia

The British newspaper published an article on Wednesday that says it was alerted by a source in Riyadh that it was being targeted by the unit following the murder of journalist Jamal Khashoggi.

It later received a copy of a document that supported the claim. According to the newspaper, which said it could not verify its authenticity, the memo authorized "the penetration" of its servers and accounts belonging to two of its reporters.

The order was signed, according to the Guardian, by a top aide and confidant of Saudi Crown Prince Mohammed bin Salman.

The story published by the Guardian did not say whether any attempts to access its networks had been detected. Spokespeople for the newspaper did not immediately respond to requests for comment.

Representatives of the government of Saudi Arabia did not immediately respond to questions from CNN. But Saudi officials told the Guardian they were "extremely concerned as to the provenance of the documents."

"The kingdom of Saudi Arabia have exceptionally strict anti-cybercrime laws and take these kinds of allegations very seriously," they said. "The kingdom has itself been a victim of serious hacking attempts in the past."

According to the Guardian, however, Saudi officials "refused to provide a statement denying any hacking operation had started or was continuing" for several weeks.

The paper revealed the alleged hacking order after a UN special report published Wednesday found "sufficient credible evidence" that bin Salman bears responsibility for the murder of Khashoggi. The Washington Post columnist was killed in the Saudi consulate in Istanbul in October.

The UN report said a further investigation should determine whether the "threshold of criminal responsibility has been met."

Media outlets have been targeted by hackers in the past.

In 2013, the New York Times reported that Chinese hackers had infiltrated its computer systems and gathered passwords for reporters. The attack followed the publication of a sensitive story about the country's leadership.

Beijing told the newspaper at the time that "Chinese laws prohibit any action including hacking that damages internet security."