Up to 21 people were killed in Friday's attack on a restaurant popular with foreigners in the Afghan capital, after a bomber blew himself up near the entrance and gunmen burst in to spray diners with bullets.
The International Monetary Fund's (IMF) representative in Afghanistan and four United Nations staff were among the dead, who included 13 foreign nationals, police said.
Taliban claimed responsibility for the attack on a Lebanese restaurant in the capital's central Wazir Akbar Khan district, which hosts many embassies and restaurants catering for expatriates.
"Such targeted attacks against civilians are completely unacceptable and are in flagrant breach of international humanitarian law," U.N. spokesman Farhan Haq said. "They must stop immediately."
The stutter of gunshots rattled the district for several minutes after the blast around 7.30 p.m., a busy dining time when expatriates in Kabul tend to eat out.
One of the survivors, Suleiman, who worked as a cook at the restaurant, said he escaped from the gunmen after hearing the explosion outside.
"I went to the roof and stayed with my back to the chimney for two or three hours. Later Afghan police came and took me out."
A clearance operation continued for several hours after the attack as until midnight police were still unsure whether more bombers might be lurking in the dark, dusty streets.
IMF representative Wabel Abdallah, a 60-year-old Lebanese national, was killed in the explosion, the IMF said. He had been leading the Fund's office in Kabul since 2008.
"This is tragic news, and we at the Fund are all devastated," Managing Director Christine Lagarde said in a statement. "Our hearts go out to Wabel's family and friends, as well as the other victims of this attack."
Security sources said other victims included civilians from Europe, Britain and Russia.
Canadian Foreign Affairs Minister John Baird said two Canadians died in the attack but it was not clear if this figure was in addition to the deaths reported by the IMF and United Nations.
State Department spokeswoman Jen Psaki said none of the dead included U.S. Embassy staff in Kabul.
After the explosion, two gunmen stormed into the restaurant and started shooting at diners, security sources said, adding that foreign casualties had been taken to an international military camp in eastern Kabul.
Outside a morgue at a nearby hospital, Afghans screamed and cried as they mourned attack victims, some pressing scarves to their faces to stifle sobs. One young man, grieving for his dead father, kicked a wall and howled.
"One of the restaurant's cooks was injured," said a doctor, Abdul Bashir. "Two dead bodies have been taken to the morgue."
A Taliban spokesman said on Twitter that the attack was revenge for an airstrike that had killed civilians in Parwan province this week.