The United States Central Intelligence Agency has vowed to avenge the deaths of seven of its agents in a suicide bombing in Afghanistan.
But first the agency is investigating the security breaches that allowed the second deadliest attack the CIA has experienced since the bombing of the US Embassy in Beirut in 1983.
The BBC reports that little is known about the agents killed in this week's attack. Neither their names nor the details of their work have been disclosed.
They died when a bomber wearing an explosive vest entered a US base in Khost province, near the border with Pakistan on Wednesday.
Taliban says one its members did it
The Taliban says the attack was carried out by one of its members working for the Afghan army.
The base is reportedly used by provincial reconstruction teams - which include soldiers and civilians - and is protected by some 200 Afghan soldiers.
It is also reportedly used for drone attacks. The CIA has courted controversy for operating unmanned drones that attack extremist targets in Pakistan - the latest of which has killed at least two people travelling in a car in the tribal region of North Waziristan.