The Clinton Foundation acknowledged Thursday that it had received millions of dollars in payments that had not previously been disclosed under a 2008 ethics agreement with the Obama administration. 

The Washington Post, citing foundation officials, reported that the payments were categorized internally as "revenue" instead of donations, which exempted the organization from including them in its public list of contributions.

Former Secretary of State Hillary Clinton, the frontrunner for the 2016 Democratic presidential nomination, has faced questions about whether the foundation fully complied with the agreement it made with the Obama administration when Clinton was nominated to be America's top diplomat. Questions have also been raised about whether the foundation's lengthy list of donors tied to foreign governments presented a conflict of interest for Clinton while she was Secretary of State or whether such conflicts might arise should she become president. 

According to the Post, the previously undisclosed money was paid in the form of speaking fees for Hillary and former President Bill Clinton, as well as their daughter Chelsea. The foundation does not say how much the Clintons were paid for each speech, only giving a range. The total amount in new payments is between $12 million and $26.4 million.

According to new information released by the foundation, the Clintons have made a total of 97 speeches to benefit the foundation since 2002. Those speeches have been sponsored by a number of institutions, including colleges and universities, corporations, and at least one foreign government, Thailand.

The Post reports that the organizations that paid to hear Hillary Clinton speak to them include large financial institutions Goldman Sachs and JP Morgan Chase. Another organization, founded by Mexican billionaire Carlos Slim, paid between $250,000 and $500,000 to hear the former Secretary of State. In all, 15 speeches by Hillary Clinton were newly disclosed by the foundation, which did not provide any dates for the events. 

Former President Bill Clinton gave 73 of the 97 newly disclosed speeches, including the speech paid for by Thailand's Energy Ministry, which contributed between $250,000 and $500,000.  Other organizations addressed by Bill Clinton include the U.S. Islamic World Forum (between $250,000 and $500,000 contributed), a South Korean energy and chemical company ( between $500,00 and $1 million), the China Real Estate Development Corp., and the Qatar First Investment Bank (both paying between $250,000 and $500,000). 

Click for more from The Washington Post.