Around 40 people were killed and dozens more wounded when a suicide bomber blew himself up inside a Shiite cultural centre in Kabul on Thursday, officials said, in the latest violence to hit the city.
There was no immediate claim of responsibility but the Taliban was quick to deny involvement in the assault near the Afghan Voice Agency, a media outlet which earlier reports had suggested could have been the target.
Deputy interior ministry spokesman Nasrat Rahimi told AFP the attack was in fact aimed at the Shiite Tabayan cultural centre in the west of the city.
"The suicide attacker detonated himself during a gathering at Tabayan cultural centre causing a lot of casualties," Rahimi said.
The main explosion was followed by two smaller bomb blasts that did not cause casualties, he said, adding that the gathering was being held to mark the 38th anniversary of Soviet invasion in Afghanistan.
There were chaotic scenes at the Istiqlal hospital where ambulances brought victims, including women and children. Many of them were suffering severe burns to their faces and bodies, as well as shrapnel wounds, AFP reporters said.
Anguished relatives searching for their loved ones inside the medical facility, slapping their heads in fury as they cried and cursed the government for seemingly being unable to end the regular carnage on their streets.
Some were so distraught they crawled on the ground pulling their hair.
An AFP reporter saw badly burned bodies lying on the floor in a room inside the hospital and wooden coffins being delivered so families could take away their dead loved ones.
Kabul has become one of the deadliest places in war-torn Afghanistan for civilians in recent months, as the Taliban step up their attacks and the Islamic State group (IS) seeks to expand its presence in the country.
Thursday's assault comes days after a suicide bomber killed six civilians in an attack near an Afghan intelligence agency compound in the city, which was claimed by IS.
The Middle Eastern jihadist group has gained ground in Afghanistan since it first appeared in the region in 2015 and has scaled up its attacks in Kabul, including on security installations and the country's Shiite minority.
A man attending the anniversary ceremony at Tabayan said he heard a "big boom".
"We do not know the numbers (of casualties). When the explosion happened we immediately fled," he told Tolo News.
Mohammad Hasan Rezayee, a university student also at the ceremony, told Tolo News he had suffered burns to his face in the blast.
"We were inside the hall in the second row when an explosion from behind took place. I did not see the bomber who detonated himself," he said from his hospital bed.
"After the blast there was fire and smoke inside the building and everyone was pleading for help," he said.
Photos posted on Afghan Voice Agency's Facebook page showed the inside of a compound with debris and bodies lying on the ground.
Security in Kabul has been ramped up since May 31 when a massive truck bomb ripped through the diplomatic quarter, killing some 150 people and wounding around 400 others -- mostly civilians. No group has yet claimed that attack.
IS, a Suni extremist group, has claimed most of the attacks on Shiite worshippers as it seeks to stir up sectarian violence in the country.
Afghan media has also previously been targeted by militants, underlying the risks faced by journalists in the war-torn country.