On Monday, Sen. Thom Tillis, R-NC, sent a letter to Paul Abbate, deputy director of the Federal Bureau of Investigation (FBI), demanding answers concerning recent cyberattacks on President-elect Donald Trump’s nominee for FBI director, Kash Patel.

Law enforcement officials told NBC News last week that the FBI recently confirmed to Patel that he had been the target of an Iranian-backed cyberattack. Hackers targeted Patel’s communications, but it remains unclear if the attack was successful in accessing the information and how much, if any, data was stolen or viewed.

In a letter to Deputy Director Abbate, Tillis expressed his concerns that such an attack had targeted Patel, as well as also the speed at which potentially classified information spread through the news cycle.

“The release of this information raises major national security and personal safety concerns,” writes Tillis in the letter.

Tillis gave the FBI a deadline of December 20 to respond to questions outlined in the letter.

Patel was previously chief of staff to Acting Secretary of Defense Christopher C. Miller during Trump’s first term.

“Kash Patel was a key part of the first Trump administration’s efforts against the terrorist Iranian regime and will implement President Trump’s policies to protect America from adversaries as the FBI Director,” said Alex Pfeiffer, spokesman for the Trump transition team.

The Trump campaign was also targeted by Iranian operatives allegedly working for the Islamic Revolutionary Guard Corps. Three operatives were charged in September with leaking emails and documents to media outlets in an effort to undermine Trump’s campaign, according to NBC News.

Current FBI Director Christopher Wray announced Wednesday to the FBI workforce that he intends to resign at the end of President Biden’s term in January. Wray was appointed to his position in 2017 by then-President Trump after he fired James Comey, FBI director at the time.

“My goal is to keep the focus on  our mission — the indispensable work you’re doing on behalf of the American people every day,” said Wray. “In my view, this is the best way to avoid dragging the bureau deeper into the fray, while reinforcing the values and principles that are so important to how we do our work.”