Former U.S. Secretary of State Colin Powell and aides to his successor, Condoleezza Rice, both received classified information a handful of times via personal email accounts, the top Democrat on a congressional oversight panel said on Thursday.

The findings come after nearly a year of controversy over Democratic presidential candidate Hillary Clinton's decision to set up a private email server for her work as secretary of state. Democratic lawmakers and staff on Clinton's presidential campaign seized on the report as vindicating some of their defenses of the controversial arrangement.

Representative Elijah Cummings said the disclosures about Powell's and Rice's aides' emails were made by the State Department's inspector general, who is reviewing the email practices of the last five secretaries of state.

That office told the State Department on Wednesday that it found 12 emails containing classified information sent to Rice's aides or Powell, according to Cummings, who is the ranking Democrat on the House of Representatives Oversight Committee.

In a statement, Powell said the two emails he received were not judged to contain confidential information at the time they were sent to him by American ambassadors.

"I wish they would release them," Powell told NBC News, "so that a normal, air-breathing mammal would look at them and say, 'What's the issue?'"

A representative for Rice, who, as with Powell, served under Republican President George W. Bush, said the 10 emails sent to her aides did not contain intelligence information.

More than 1,500 of Clinton's emails, which are being made public on a federal judge's order, have been found to include classified information so far, according to the State Department.

Clinton both sent and received information the State Department now deems to be classified, including the privately shared thoughts of foreign leaders, as well as highly classified U.S. intelligence agency secrets.

It became public last March that Clinton set up a private email server in her New York home for her work as President Barack Obama's secretary of state between 2009 and 2013. Accusations that she exposed government secrets to hackers and tried to side-step record keeping laws have since dogged her campaign, and the arrangement is being examined by the Federal Bureau of Investigation.

Clinton's campaign staff suggested the findings announced on Thursday helped vindicate her claim that she did nothing wrong or unusual and repeated their accusation that the State Department is overclassifying her emails, an idea the department has dismissed.

"Hillary Clinton agrees with her predecessor that his emails, like hers, are being inappropriately subjected to over-classification," John Podesta, Clinton's campaign chairman, said in a statement, calling for their unredacted release.

J. William Leonard, who oversaw the government's classification regime as the Information Security Oversight Office director until 2008, said so-called "spillage" of classified information into unsecured email systems was common.

"That's why from the get-go it was exceedingly poor judgment to set up a private email account because of this very real fact," Leonard said in an interview, referring to Clinton's arrangement.

The government forbids sending classified information via email, but the .gov email system, which Clinton circumvented, is monitored and protected on the assumption that classified information spills into it.

Powell has said the State Department was technologically backward when he joined in 2001 and that he had to fight to get an Internet-connected computer installed in his office, from which he continued to use his personal email account.

Georgia Godfrey, Rice's chief of staff at Stanford University's Hoover Institution, said Rice did not use email while at the State Department, and that the 10 emails to her staff were reports on "diplomatic conversations."

Government regulations require that information shared in confidence by foreign government officials should be treated as classified.

(Additional reporting by Jonathan Allen in New York; Editing by Andrew Hay and Tom Brown)