The National Security Agency (NSA) warned White House officials against using private email accounts soon after President Trump took office, Politico reported Friday.

A former senior U.S. intelligence official said NSA officials gave classified briefings to White House officials on the security threats posed by using private email addresses and personal cell phones.

The NSA officials told members of Trump's White House that their personal cell phones could be hacked and used for spying purposes, and also told them to assume that their personal email accounts had already been accessed by foreign spies.

The former intelligence official told Politico that former White House chief of staff Reince Priebus and Homeland Security adviser Tom Bossert both attended the briefing. Trump's son-in-law and senior adviser Jared Kushner was expected to attend the meeting, the official said, but it's unclear if he did.

The report follows news that Kushner has used a private email account to communicate with other Trump administration officials about White House business. Politico reported Friday that the NSA briefings came before Kushner and other top aides used their personal email and phones for official business.

Kushner has reportedly used the email to discuss media planning and event coverage with White House officials including Priebus, former chief strategist Stephen Bannon and chief economic adviser Gary Cohn.

The two top members of the Senate Intelligence Committee sent a letter to Kushner via his attorney this week, accusing him of not revealing the existence of the account.

"The Committee was concerned to learn of this additional email account from the news media, rather than from you, in your closed staff interview," Sens. Richard Burr (R-N.C.) and Mark Warner (D-Va.) wrote.

"Please confirm that the document production that you made to the committee ... included the additional 'personal email account' described to the news media, as well as all other email accounts messaging apps, or similar communications channels you may have used."