A congressional committee investigating the 2012 attack on a U.S. Consulate in Libya issued subpoenas on Wednesday for former Secretary of State Hillary Rodham Clinton's personal emails, which have created a political storm for the presumptive Democratic presidential candidate.

The U.S. House of Representatives Select Committee on Benghazi demanded all communications from Clinton related to the incident, in which a U.S. ambassador was killed.

The panel also sent letters to Internet companies telling them to protect any documents relevant to the ongoing investigation, Jamal Ware, communications director for the Benghazi committee, said in a statement.