John Kelly's phone was reportedly compromised for months

Kevin Lamarque/Reuters

White House chief of staff John Kelly's personal cell phone has been compromised for months, raising concerns that hackers or foreign governments had access to Kelly's communications during his time in President Donald Trump's administration, Politico reported on Thursday.

The issue was discovered after Kelly gave his phone to White House tech staff this summer, telling them that the device hadn't been working properly for months. The IT department determined that the phone may have been compromised beginning in December 2016.   

A White House official told Politico that Kelly used his government-issued phone for most communications since he joined the administration as Trump's secretary of homeland security. Kelly became chief of staff in July. 

The details surrounding when, where, or how the phone was compromised, and what information might have been accessed, are all unclear, Politico reported. 

In September, the White House circulated a one-page memo detailing the breach and aides are now encouraged to minimize their use of private phones in the White House or to keep them in lockers while at work.

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