Secretary of State Hillary Clinton has lashed out at a senator who accused the Obama administration of misleading the public over a raid on a US consulate.
A member of the Senate foreign relations committee suggested there had been a cover-up of events surrounding the assault in Benghazi. Mrs Clinton thumped the table as she clashed with Senator Ron Johnson.
Earlier in the hearing, she took responsibility for security failures that led to the attack.
Mrs Clinton will be grilled later on Wednesday in the House of Representatives, where she is expected to face even more heat.
The US envoy to Libya, Christopher Stevens, and three other officials were killed in the raid on 11 September. The ambassador died of smoke inhalation when he was trapped in the burning consulate building, after armed men stormed the compound.