Google said state-based hackers have targeted the campaigns of both President Donald Trump and former Vice President Joe Biden, although it saw no evidence that the phishing attempts were successful.

The company confirmed the findings after the director of its Threat Analysis Group, Shane Huntley, disclosed the attempts Thursday on Twitter. 

Huntley said a Chinese group known as Hurricane Panda targeted Trump campaign staffers while an Iranian outfit known as Charming Kitten had attempted to breach accounts of Biden campaign workers. Such phishing attempts typically involve forged emails with links designed to harvest passwords or infect devices with malware.

The effort targeted personal email accounts of staffers in both campaigns, according to the company statement. A Google spokesman added that "the timeline is recent and that a couple of people were targeted on both campaigns.” He would not say how many.

Google said it sent targeted users “our standard government-backed attack warning” and referred the incidents to federal law enforcement.