Afghan authorities say the death toll from a Taliban attack on a Lebanese restaurant in Kabul, frequented by foreigners and affluent Afghans, rose to 21 on Saturday.
An International Monetary Fund official as well as four United Nations personnel are among the dead.
The U.S. Embassy said Saturday two private U.S. citizens were among those killed.
U.S. Ambassador James Cunningham said the Taliban target people who "have hope in and work for" Afghanistan's success. He said the insurgents "only destroy, they cannot build."
Authorities say a suicide bomber blew himself up outside the restaurant Friday and that two gunmen entered the establishment and opened fire. The gunmen also were killed.
The commander of NATO's International Security Assistance Force in Afghanistan, Gen. Joseph Dunford, condemned the Taliban attack and urged the group to stop what he called "the premeditated and indiscriminate slaughter of civilians."
General Zahir Zahir, the Kabul police chief, spoke to VOA by phone about the attackers.
"One of them blew himself up in front of the restaurant and two of them entered the structure and engaged with the guards. Eventually police arrived to the scene and cleaned up the place. The police have the complete situation under control."
The International Monetary Fund said its representative in Afghanistan, 60-year-old Lebanese national Wabel Abdallah, was killed.
IMF Managing Director Christine Lagarde issued a statement saying, "This is tragic news, and we at the fund are all devastated."
A statement attributed to the spokesperson for U.N. Secretary-General Ban Ki-moon said Mr. Ban condemns in the strongest terms the horrific attack that left the four U.N. staffers dead. The statement said such targeted attacks against civilians are completely unacceptable, are in flagrant breach of international humanitarian law and must stop immediately.
The U.N. Security Council stressed the need to bring the "perpetrators, organizers, financiers and sponsors of these reprehensible acts of terrorism to justice."
A number of embassies and foreign organizations have offices in the area of the attack, and many Afghan officials live nearby.