A powerful explosion has killed more than 50 worshippers after Friday prayers at a Kabul mosque, the latest of a series of attacks on civilian targets in Afghanistan during Ramadan. The blast hit the Khalifa Sahib mosque in the west of the capital in the early afternoon, according to Besmullah Habib, the deputy spokesperson for the interior ministry. The attack came as worshippers at the Sunni mosque gathered after Friday prayers for a congregation known as Zikr – an act of remembrance practised by some Muslims but seen as heretical by several Sunni groups. Sayed Fazil Agha, the head of the mosque, said someone they believed was a suicide bomber joined them in the ceremony and detonated explosives. “Black smoke rose and spread everywhere, dead bodies were everywhere,” he said, adding that his nephews were among the dead. “I survived, but lost my beloved ones.” A local resident, Mohammad Sabir, said he had seen people being loaded into ambulances. “The blast was very loud. I thought my eardrums were cracked,” he said. The emergency hospital in downtown Kabul said it was treating 21 patients wounded in the blast and two were dead on arrival. A nurse at another hospital, who declined to be identified, said it had received several people in a critical condition. A health source said hospitals had so far taken in at least 30 bodies in total. Scores of Afghan civilians have been killed in recent weeks in blasts, some of which have been claimed by Islamic State (IS). The latest attack came on the last Friday in the month of Ramadan, in which most Muslims fast, and before the religious holiday of Eid next week. The Taliban rulers say they have secured the country since taking power in August and largely eliminated IS’s local offshoot. However, international officials and analysts say the risk of a militant resurgence remains. Many of the attacks have targeted the Shia minority but Sunni mosques have also been attacked. Bombs exploded on two passenger vans carrying Shia Muslims in the northern city of Mazar-e-Sharif on Thursday, killing at least nine people. Last Friday, a blast tore through a Sunni mosque during Friday prayers in the city of Kunduz, killing 33.