WASHINGTON (Reuters) - Secretary of State Hillary Clinton will appear before the U.S. Senate Foreign Relations Committee on Wednesday, January 23, to answer lawmakers' questions about the September attack on U.S. diplomatic sites in Benghazi, Libya, the panel said, the same day she will appear before the House of Representatives Foreign Affairs Committee.

Clinton's testimony had been delayed for several weeks after she sustained a head injury. Her appearance will clear the way for the confirmation hearing for Senator John Kerry to succeed Clinton as secretary of state, which is now set for Thursday, January 24. Kerry is the current chairman of the Foreign Relations Committee.

Republican legislators had said they wanted to hear directly from Clinton before she leaves office about the Benghazi attacks, in which U.S. Ambassador to Libya Christopher Stevens and three other Americans died.

Democratic Senator Robert Menendez, who is due to succeed Kerry as chairman of the Senate panel, will preside over Kerry's confirmation hearing. Kerry, a Massachusetts senator and former Democratic presidential nominee, is expected to be easily confirmed as the United States' top diplomat.

(Reporting by Patricia Zengerle; Editing by Eric Beech)