In a trove of newly leaked emails, former Secretary of State Colin Powell calls Donald Trump "a national disgrace" and suggests his own Republican Party is "crashing and burning."

Powell also laments Hillary Clinton's attempt to equate her use of private email at the State Department with his.

The emails, posted on the website DCLeaks.com and first reported by Buzzfeed News late Tuesday, offer insight into the unvarnished opinions of the respected retired Army general who was secretary of state under President George W. Bush. The messages run from March 2015 through last month.

Powell, 79, did not respond Wednesday to a phone message or email seeking comment. He earlier told BuzzFeed that he does not deny the emails' authenticity.

In the emails, Powell said he stayed relatively quiet during the rise of Trump, the Republican presidential nominee. "To go on and call him an idiot just emboldens him," Powell said.

No need to debate it with you now, but Trump is a national disgrace and an international pariah. - Colin Powell, email posted on DCLeaks.com

To a former aide he writes, "No need to debate it with you now, but Trump is a national disgrace and an international pariah."

He also criticized Trump for backing the false claim that President Barack Obama was not born in the United States.

"All his lies and nonsense just pile up," Powell wrote. "I just go back to the unforgivable one. Trying to destroy the President elected by the American people with his fictitious investigation into this source of birth. Absolutely disgraceful."

I was never a fan of Colin Powell after his weak understanding of weapons of mass destruction in Iraq = disaster. We can do much better! —@realDonaldTrump

Powell, a Republican, but one who twice endorsed Obama for president, also suggests frustration with the state of the nation's politics.

"We all need to start voting for America and not our parties," Powell writes. "Trump is taking on water. He doesn't have a GOP philosophy or even a Conservative philosophy. We need a revolution and it will begin with the GOP crashing and burning up its current form."

DCLeaks.com has been alleged to be an outlet for hackers tied to the Russian intelligence groups. The website, which says it intends to expose the misuse of political power, has previously released emails from other Washington political figures.

Campaign riddled with leaks

The release of Powell's emails is the latest in a string of leaks that appear intended to influence the 2016 presidential election. The FBI is investigating how thousands of Democratic National Committee emails were hacked and released, an embarrassing breach that Clinton's campaign maintains was committed by Russia to benefit Trump.

Powell's leaked messages include his thoughts on Clinton's lingering email woes. He criticized Clinton aides for tying him into the controversy over the Democratic nominee's use of a private email server while she was secretary of state.

Powell has acknowledged using a private email account with both senior U.S. officials and for back-channel communications with foreign dignitaries. Clinton used a private email server located in the basement of her New York home.

Everything HRC touches she kind of screws up with hubris. - Colin Powell, email posted on DCLeaks.com

Powell wrote that he had told Clinton's "minions repeatedly that they are making a mistake trying to drag me in, yet they still try." In another spot, he declared of Clinton that "Everything HRC touches she kind of screws up with hubris."

The messages contain comments that reflect that he, too, sought to use private email as a way to avoid creating documents retained by the government. Decrying "friggin record rules," Powell wrote that he "saw email more like a telephone than a cable machine."

Congressional Democrats have seized on the use of a private email addresses by Powell and former Secretary of State Condoleezza Rice as a foil for Republican attacks on Clinton. By suggesting that he didn't view work conducted via private email as a permanent government record, Powell could offer those Democrats additional ammunition.

In May, Powell messaged with a former colleague as the State Department's inspector general prepared to release a report critical of both his and Clinton's use of private email to conduct government business.

"Wow, I didn't follow rules," Powell wrote. "I only revolutionized the information system in the entire State Department. ... I think I'll bash the Department tomorrow. Fifteen years later they come up with this. ... Thanks Hillary."

New York, Florida inquiries

Meanwhile, New York Attorney General Eric Schneiderman said on Tuesday he had opened an inquiry into the Donald J. Trump Foundation to ensure the charity was complying with state laws governing non-profit organizations.

Schneiderman, a supporter of Trump's Democratic rival in the presidential race, Hillary Clinton, sued the real estate mogul and his now-defunct Trump University for fraud in 2013, seeking $40 million in restitution plus penalties and other costs.

In a CNN interview on Tuesday, Schneiderman said his office has now brought Trump's charitable foundation under scrutiny.

"My interest in this issue, really, is in my capacity as regulator of non-profits in New York state. And we have been concerned that the Trump Foundation may have engaged in some impropriety from that point of view," the elected Democratic official said, without elaborating.

Trump campaign spokesman Steven Cheung dismissed Schneiderman's assertions as entirely motivated by presidential politics, calling the attorney general a "partisan hack who has turned a blind eye to the Clinton Foundation for years."

Cheung called Schneiderman's comments "nothing more than another left-wing hit job designed to distract" attention from Clinton's recent missteps on the campaign trail.

New York Attorney General Eric Schneiderman speaks in Albany, N.Y. in May. (Mike Groll/Associated Press)

Congressional Democrats are calling for an investigation into a $25,000 donation the Trump Foundation made in 2013 to a political committee supporting Florida's Republican attorney general Pam Bondi.

Democrats have cited an Associated Press report that Bondi solicited the donation personally, around the time her office was debating whether to join New York state's investigation into Trump's real estate training school in Florida. According to the AP, Bondi, who was seeking re-election at the time, broke off the lawsuit deliberations after the cheque arrived.

The payment raises the question of whether Bondi was bribed, said Congressman Jerrold Nadler of New York.

"That is not how the system is supposed to work," Nadler said during a Wednesday morning news conference, flanked by other Democratic members of the House Judiciary Committee.

"That is rigging the system."

​Bondi, who has endorsed Trump, has called the AP report misleading.

Also on Wednesday, Newsweek magazine published a cover story on Trump which the U.S. magazine claims could change the election. The story links Trump's organization to foreign powers, international financial players and even criminals. It says Trump's deals around the world would "make it impossible" for him to conduct foreign policy "without padding or depleting his wallet."

Trump has accused Clinton of being corrupted by donors to the Clinton Foundation — the global charity founded by her husband, former president Bill Clinton — while she was U.S. secretary of state from 2009 to 2013.

Clinton has dismissed Trump's allegation as a political smear. There has been no evidence that foreign donors to the foundation obtained favours from the State Department while Clinton headed the agency.