Sidney Blumenthal, a longtime adviser who sent then-Secretary of State Hillary Rodham Clinton more than two dozen back-channel reports about unrest in Libya, said on Thursday night that he provided it "as a private citizen and friend," and that it was merely information "I thought she might find interesting or helpful."

Those messages, sent at a time when Blumenthal was working for the Clinton family foundation and with entrepreneurs who hoped to do business in Libya, have drawn the interest of the House Select Committee on Benghazi, which is investigating the 2012 attack in which U.S. ambassador J. Christopher Stevens and three other American officials were killed.

The panel subpoenaed Blumenthal to testify, and he said in the statement, issued through his lawyer James M. Cole, that he "will cooperate with its inquiry and look forward to answering the Committee's questions."

Blumenthal's e-mails were among 300 that have been turned over to the panel by the State Department, and were published Thursday by the New York Times. They had been sent to Clinton via a personal e-mail address that she used while at the State Department. Her use of the private account violated White House guidelines at the time, which stipulated using government e-mail for official business when possible.

Clinton passed along the information from Blumenthal down the chain to other State Department officials, who reportedly were skeptical of much of it. The Obama White House had previously blocked Clinton's efforts to appoint Blumenthal to a position in the State Department because the president's team believed he was unreliable.

Clinton's presidential campaign has downplayed the significance of the e-mail correspondence, and of her handling of it.

"Sid provided unsolicited thoughts and suggestions to the Secretary on a variety of topics.  He was not a U.S. government employee nor asked by the Secretary to do so," spokesman Brian Fallon said by e-mail.