The email hack of Democratic National Committee officials has widened to include the personal account of a staffer researching Donald Trump advisor Paul Manafort's Russian political ties, according to a report from Yahoo's Michael Isikoff.

In correspondence dated May 3, Democratic consultant Alexandra Chalupa wrote that she began receiving Yahoo security messages warning that her email had been "the target of state-sponsored actors".

"Since I started digging into Manafort these messages have been a daily occurrence on my yahoo [sic] account despite changing my password often," Chalupa wrote to DNC communications director Luis Miranda.

More from Isikoff:

... Chalupa's message, which had not been previously reported, stands out: It is the first indication that the reach of the hackers who penetrated the DNC has extended beyond the official email accounts of committee officials to include their private email and potentially the content on their smartphones. After Chalupa sent the email to Miranda (which mentions that she had invited this reporter to a meeting with Ukrainian journalists in Washington), it triggered high-level concerns within the DNC, given the sensitive nature of her work. "That's when we knew it was the Russians," said a Democratic Party source who has been directly involved in the internal probe into the hacked emails. In order to stem the damage, the source said, "we told her to stop her research."

A Yahoo spokesman said the pop-up warning to Chalupa "appears to be one of our notifications" and said it was consistent with a new policy announced by Yahoo on its Tumblr page last December to notify customers when it has strong evidence of "state sponsored" cyberattacks. "Rest assured we only send these notifications of suspected attacks by state-sponsored actors when we have a high degree of confidence," wrote Bob Lord, the company's Chief Information Security Officer, in the Tumblr post.

Read the report here.