U.S. Secretary of State John Kerry has been subpoenaed over the 2012 attack in Benghazi, Libya.
The U.S. House of Representative's Oversight Committee issued the subpoena on Friday.
Kerry will have to testify on May 21 about the attack on the U.S. consulate that killed the American ambassador and three other Americans.
Committee Chairman Darrell Issa said the panel wants Kerry to answer questions about the State Department's response to a congressional investigation of the attack.
Benghazi has become a political issue for Republicans.
They say President Barack Obama's administration didn't do enough to help the Americans in Benghazi and then focused on protecting Obama's image during an election year.
Benghazi also has political implications for Hillary Clinton.
She was secretary of state at the time of the attack and is a likely presidential candidate in 2016.