The hacker suspected of breaching the US Democratic National Committee has released another trove of internal documents containing financial documents, staff lists, donor records and memos marked as 'private and confidential'.

This is the second such release of data stolen from the Democratic Party by a suspected Russian state-sponsored cybercriminal known as 'Guccifer 2.0' and comes only days after the controversial leak of a strategy playbook compiled on rival presidential hopeful, Donald Trump.

The latest release consists of 21 new documents, each uploaded to a WordPress-hosted website in Windows Excel and PDF formats. Titles include 'Hillary for America Fundraising Guidelines', 'Private Memorandum to Ashton Carter', 'staff' and 'paid media traffic'.

Viewed by IBTimes UK, the aforementioned donor lists include names, email addresses, home addresses, financial amounts donated to the campaign, employer's organisation and ZIP codes. The personnel records contain full description of Democratic Party staffers – names, positions and biographies.

On his basic website, hosted on the open internet, Guccifer wrote: "It appears there are a lot of financial reports, donor lists and their detailed personal information including email addresses and private cell phone numbers. Ha! Ha! Ha! Who still doubts I extracted more than 2 files? I got tons of files and docs. Hope you'll appreciate it."

The hacker added: "Wait for another part! You won't regret. Together we'll be able to throw off the political elite, the rich clans that exploit the world!" No timescale for future releases was provided.

When the news first emerged of the hacking incident, The Washington Post quoted DNC sources who claimed that no sensitive information was compromised in the attack. Now, if legitimate, this latest release appears to contradict the official party line.

Hillary: Hack is 'troubling'

As previously reported, the Democratic Party-related committee said it had evidence showing that state-sponsored hackers had infiltrated its computer networks and lay dormant there for over a year monitoring chats, emails and internal communications.

CrowdStrike, the cybersecurity firm brought in to investigate the incident, later asserted that two separate Russia hacking groups had access to the networks.

Hillary Clinton, the presidential hopeful for the Democratic Party in the upcoming US election, responded to the hack by calling the situation "troubling." She said: "I only learned about it when it was made public and it is troubling, as all cyberattacks against our businesses and our institutions and our government are."

She continued: "The [Russian] government uses cyberattacks to gain information to be used for economic commercial advantage, for political advantage and for military advantage. This seems like another example where they are trying to vacuum up information. Why? We don't know yet.

"So far as I know – my campaign has not been hacked into but cybersecurity will be an issue that I will be absolutely focused on as president because whether it's Russia, China, Iran or North Korea more and more countries are using hacking to steal out information. We can't let that go on."

Russian officials have denied involvement with the hacking incident. The advisor to Russian president Vladimir Putin, German Klimenko, said it was likely that "someone simply forgot the password".

Donald Trump, who was of course directly implicated in the cyberattack, responded by claiming the Democratic Party had orchestrated the hack on itself. In an official statement, he said: "We believe it was the DNC that did the 'hacking' as a way to distract from the many issues facing their deeply flawed candidate and failed party leader."