Afghan officials say more than 40 people have been killed and 84 others wounded in a suicide attack on a building in Kabul that houses a Shi'ite Muslim cultural center with ties to Iran.
A spokesman for Afghan Ministry of Public Health told reporters that four women and two children were among those killed in the blast.
Islamic State claimed responsibility for the attack. An online statement said the attack was carried out by a suicide bomber, and that three other bombs were also used. Previous attacks on Shi'ite worship places and processions in Kabul and elsewhere in Afghanistan were also claimed by Islamic State.
The bomber, witnesses reported, blew himself up near a big meeting in the basement of the Tebyan Social and Cultural Center building shortly before other devices went off.
Responding to criticism over a lack of security around the building, Afghan officials said the cultural center did not inform police prior to holding Thursday's event.
The offices of the Afghan Voice Agency (AVA), a news organization, are near the cultural center. Reuters reports that at least one AVA journalist is among those killed.
President Ashraf Ghani called the attack a "crime against humanity."
The presidential palace said in a statement the Afghan government is committed to eliminating terrorism.
"Terrorists groups and their backers must know that the Afghan people are united and stand firm to any plot carried out by their enemies; these heinous attacks will not break the resolve of the Afghan people," the statement read.
The White House issued a statement Thursday that condemned the attack and offered "its deepest condolences to the victims and their families."
"The United States stands firmly with the government and people of Afghanistan and will work closely with the National Unity Government to bring the perpetrators of this heinous attack to justice. The enemies of Afghanistan will not succeed in their attempts to destroy the country and divide the Afghan people, who are resilient and committed to establishing peace and stability," the statement said.
NATO's Resolute Support mission in a statement condemned the bloodshed.
"Cultural advancement and freedom of speech will not be deterred. Our mutual enemies must know they will not win and the Afghan people will not be silenced," said the mission, which comprises mostly American troops.
The U.N. Assistance Mission in Afghanistan called the attack "another truly despicable crime in a year already marked by unspeakable atrocities."
The Taliban insurgency distanced itself from the attack, saying its fighters do not target civilian facilities, especially those housing education and cultural centers.
Meanwhile, an overnight bomb blast in the northern province of Balkh killed at least six children. The incident took place in the district of Dawlatabad. Officials reported the victims found an improvised explosive device planted by anti-government militants, and were playing with it when it exploded.