The attack comes as security has been deteriorating and apprehension has been growing among Afghans over their country's future as U.S.-led foreign forces prepare for a final withdrawal at the end of the year.
Afghan President Hamid Karzai, who is deferring signing an agreement allowing U.S. forces to stay past the planned withdraw until after the country's April 5 presidential election, criticized America while condemning the attack.
"If NATO forces and in the lead the United States of America want to cooperate and be united with Afghan people, they must target terrorism," he said without fully elaborating on what America should be doing. He added that America had followed a policy that "was not successful in the past decade."
The dead from Friday's assault against La Taverna du Liban included 14 foreigners and eight Afghans, all civilians. The U.S. Embassy in Kabul said late Saturday that three Americans were killed. Previously, those identified included two U.S. citizens working for the American University of Afghanistan and a victim identified by the United Nations as a Somali-American.
Others identified were two Britons - development specialist Dharmender Singh Phangura and close protection officer Simon Chase - two Canadians who worked for a financial services firm, two Lebanese, a Danish police officer, a Russian, a Malaysian and a Pakistani. Phangura, who along with the Malaysian worked as an adviser for Adam Smith International, was to run as a Labour Party candidate in upcoming elections for the European Parliament.
Also among the dead were the International Monetary Fund's Lebanese representative, Wabel Abdallah, and Vadim Nazarov, a Russian who was the chief political affairs officer at the U.N. Mission in Afghanistan. Nazarov was one of the U.N's most experienced officials, fluent in the country's languages and with experience dating back to the 1980s. He was one of three U.N. victims.
The attack was condemned by the U.N. Security Council, NATO, the White House and the European Union.
"There is no possible justification for this attack, which has killed innocent civilians, including Americans, working every day to help the Afghan people achieve a better future with higher education and economic assistance," the White House said in a statement Saturday.
Insurgents have frequently targeted foreign interests around the country and in Kabul. The deadliest previous attack against foreign civilians was in Sept. 8, 2012, when nine civilian employees of a private aviation company were killed in a suicide attack happened near Kabul airport. They included eight South Africans and a Kyrgyz.
The assault began Friday with a suicide bomber detonating his explosives at the front door of the restaurant, located in an area housing several embassies, non-governmental organizations and the homes and offices of Afghan officials. As chaos ensued, the two other attackers entered through the kitchen and began shooting. They were later killed by security guards
The Taliban claimed responsibility for the attack, saying it was in reprisal for an Afghan military operation earlier in the week against insurgents in eastern Parwan province, which the insurgents claimed killed many civilians.
Afghan officials previously said that attack killed a Taliban leader, three of his family members, seven Taliban fighters and five civilians in a neighboring home from which insurgents on the Afghan commandos. The Taliban frequently provide exaggerated casualty figures.
"The target of the attack was a restaurant frequented by high-ranking foreigners," Taliban spokesman Zabihullah Mujahid said in an emailed statement. He said the attack targeted a place "where the invaders used to dine with booze and liquor in the plenty."
He described the "revenge attack" as having delivered a "heavy admonitory blow to the enemy which they shall never forget."
The restaurant, like most places frequented by foreign diplomats, aid workers, journalists and businessmen in the war-weary country, has no signs indicating its location and is heavily secured. It sits on a small side street just off a bumpy semi-paved road in a house with low ceilings and an enclosed patio but has no windows.
Bags of dirt are piled up around it to act as blast walls and guests must go through a series of steel airlocks, where they are searched, before entering. The surrounding area is full of police and security guards to protect against insurgent attacks, which have increased in recent months around the country.
"The restaurant was known to be one of the more secure in the area and has therefore been given a green-light by many expatriate and official organizations," said Michael Smith, the president of the American University of Afghanistan.
Associated Press writers Rahim Faiez in Kabul, Jan M. Olsen in Copenhagen, Denmark, and Cassandra Vinograd in London contributed to this report.