FBI investigators believe that foreign hackers targeted the cellphones of some Democratic Party figures within the last month, according to a Tuesday Reuters report.

Reuters cited four unnamed government and political sources who said some of the figures targeted may have been elected officials.

Investigators believe the hackers behind the attacks were connected to the Russian government, two of Reuters’ sources say.

In July, WikiLeaks published thousands of hacked Democratic National Committee emails just before the party’s national convention, some of which showed senior committee officials mocking Sen. Bernie Sanders’ (I-VT) campaign. The leak prompted Rep. Debbie Wasserman Schultz (D-FL) to resign as committee chairwoman.

Days later, the Democratic Congressional Campaign Committee confirmed that it had been hacked.

According to an August report from Reuters, U.S. intelligence officials told leaders in Congress that Russian hackers were behind the attack on the DNC and other Democratic Party entities a year before the hack came to light.