The leader of Kabul's Khalifa Sahib Mosque, which was targeted by an apparent suicide bombing on April 29 as worshipers gathered, has claimed that more than 50 people died in the attack.
"Black smoke rose and spread everywhere, dead bodies were everywhere," mosque leader Sayed Fazil Agha told Reuters. Agha said that the explosion at the Sunni mosque in the Afghan capital's Darul Aman district went off after someone believed to be a suicide bomber joined a ceremony following Friday prayers.
The blast reportedly took place during a congregation known as Zikr, an act of religious remembrance that is seen as heretical by some hard-line Sunni groups.
The mosque, a former Sufi monastery, was holding services on the last Friday of the Muslim holy month of Ramadan as worshipers prepared to celebrate Eid.
The official casualty count, according to a spokesman for the police force of the Taliban-led government, stands at 10 killed and more than 30 injured.
"The death toll from the blast has risen to 10 and the number of injured to 30. Detectives and security forces have launched a serious investigation into the incident," Khalid Zadran, the Taliban's police spokesman in Kabul, said in a text message to RFE/RL's Radio Azadi.
Eyewitnesses told Radio Azadi that they had seen dozens of dead and injured at the site of the blast and that the number of fatalities was higher than what security authorities had indicated.
An unidentified health worker told Reuters that hospitals had received more than 65 dead and at least 78 wounded.
Condemnation of the attack, for which no one has claimed responsibility, was swift.
Taliban spokesman Zabihullah Mujahid released a statement on April 29 in which he said the perpetrators would be found and punished.
Mette Knudsen, the UN secretary-general's deputy special representative for Afghanistan, said she was appalled by the attack.
"No words are strong enough to condemn this despicable act," Knudsen tweeted.
Pakistan's Foreign Ministry responded to the attack by saying that "we express support and solidarity to the Afghan brethren in effectively countering the challenge of terrorism."
The U.S. special envoy for Afghan women, girls, and human rights, Rina Amiri, tweeted that she was "deeply saddened to hear of yet another attack on a mosque in Kabul during the sacred month of Ramadan," and called for such violence to end and for the perpetrators to be held accountable.
A similar blast one week ago at a Sufi monastery in Kunduz's Imam Sahib district killed at least 30 people and wounded dozens more.
Afghan Hazaras, predominantly Shi’ite Muslims, and several Sunni Sufi groups have been the target of a series of attacks and bombings in Afghanistan recently. IS Khorasan (IS-K) has claimed responsibility for many bombings against Shi’a Afghans.