A mosque in Afghanistan's capital Kabul was bombed Friday, killing at least 10 and injuring more than 20 people, according to a Taliban spokesperson.

Hundreds of worshippers had gathered for prayers on the last Friday of the Muslim holy month of Ramadan and the Khalifa Aga Gul Jan Mosque was packed, said local residents, fearing the casualty toll could rise further.

The attack came as worshippers at the mosque gathered after Friday prayers for a congregation known as Zikr – an act of religious remembrance.

The Taliban's interior ministry spokesperson, Mohammad Nafi Takor, could not provide more details and Taliban security men cordoned off the area. The source of the explosion was not immediately known and no one has claimed responsibility for the blast.

The explosion was so loud that the neighborhood of the mosque shook from the blast, the residents said, speaking on condition of anonymity, fearing for their own safety.

Sayed Fazil Agha, the head of the mosque, said someone they believed was a suicide bomber joined them in the ceremony and detonated explosives and that 50 people have died.

"Black smoke rose and spread everywhere, dead bodies were everywhere," he told Reuters, adding that his nephews were among the dead. "I myself survived, but lost my beloved ones," he added.

Ambulances raced to the site, driving up to the end of a narrow street in an eastern neighborhood of Kabul to reach the mosque, which belongs to Afghanistan’s majority Sunni Muslims.

Wahid, an Afghan in his 30s, said he was home when he heard about the blast and rushed to the mosque right away, knowing his brother was there. He recalled the scene of mayhem, the screams and shouts for help. He helped carry the wounded to ambulances.

"Everyone was crying and covered in blood," Wahid said. "I was told my brother had been hurt," he added.

The Associated Press (AP) spoke to Wahid outside the Italian-run Emergency Hospital in downtown Kabul, where he had gone to give blood, but Taliban guards cordoned off the hospital, denying access to everyone but the wounded. He finally found his brother, wounded in the arm and leg.

The hospital, which treats only the war-wounded, tweeted that its staff reported the facility has admitted at least "20 wounded people" following the explosion but said it was treating 21 patients and two were dead on arrival. A nurse at another hospital, who declined to be identified, said it had received several wounded in critical condition. A health source said hospitals had so far received at least 30 bodies in total.

Javid, who appeared to be in his late 20s, said he was on his way to the mosque to join his brother and cousin who were already there when he heard the explosion. He rushed to the scene.

"I was so afraid and ran there," he said, adding that he had found both his brother and their cousin, slightly injured and released after treatment. The explosion was so powerful, Javid said, the roof of the mosque collapsed.

Wahid and Javid would only give their first names to the AP, fearing for their own safety.

The explosion was the latest in a series of such blasts amid relentless attacks across the country. Similar attacks on mosques have recently targeted the country's minority Shiite Muslims and were claimed by the Daesh terrorist group's regional affiliate, known as the Daesh-Khorasan Province (Daesh-K).

Daesh has stepped up its attacks across Afghanistan to become the primary enemy of the Taliban since their takeover of the country last August.

Last week, 33 Shiite worshippers died in the northern city of Mazar-e-Sharif, when a bomb struck their mosque and an adjacent religious school. Daesh has claimed responsibility for that attack.

A spokesperson for the Taliban, Zabihullah Mujahid, released a statement condemning the blast and saying the perpetrators would be found and punished.

The Taliban say they have secured the country since taking power in August and largely eliminated Daesh's local offshoot, but international officials and analysts say the risk of a resurgence in militancy remains.

Many of the attacks have targeted the Shiite minority, however Sunni mosques have also been attacked.