The FBI is investigating suspected attempts to hack mobile phones used by Democratic Party officials as recently as the past month, Reuters reported on Wednesday, citing four people with direct knowledge of the attack and the investigation.
The revelation underscores the widening scope of the U.S. criminal inquiry into cyber attacks on Democratic Party organizations, including the presidential campaign of its candidate, former U.S. Secretary of State Hillary Clinton.
U.S. officials have said they believe those attacks were orchestrated by hackers backed by the Russian government, possibly to disrupt the Nov. 8 election in which Clinton faces Republican Party candidate Donald Trump. Russia has dismissed allegations it was involved in cyber-attacks on the organizations.
The more recent attempted phone hacking also appears to have been conducted by Russian-backed hackers, two people with knowledge of the situation said.
Interim DNC Chairwoman Donna Brazile told CNN: "Our struggle with the Russian hackers that we announced in June is ongoing - as we knew it would be - and we are choosing not to provide general updates unless personal data or other sensitive information has been accessed or stolen."
FBI agents had approached a small number of Democratic Party officials to discuss concerns their mobile phones may have been compromised by hackers, people involved said. It was not clear how many people were targeted by the hack or whether they included members of Congress, a possibility that could raise additional security concerns for U.S. officials.
If they were successful, hackers could have been able to acquire a wide range of data from targeted cellphones, including call data, text messages, emails, photos and contact lists, one person with knowledge of the situation said.
The FBI has asked some of those whose phones were believed to have hacked to turn over their phones so that investigators could "image"
them, creating a copy of the device and related data.
U.S. investigators are looking into whether hackers used data stolen from servers run by Democratic organizations or the private emails of their employees to get access to cellphones, one person said.