An explosion rocked a Shiite mosque in northern Afghanistan's Kunduz province on Friday, killing and wounding at least 100 people, according to the UN and a Taliban official.

Witnesses reported hearing the blast as they gathered for afternoon prayers at the Gozar-e-Sayed Abad Mosque. 

"This afternoon, an explosion took place in a mosque of our Shiite compatriots ... as a result of which a number of our compatriots were martyred and wounded," Taliban spokesman Zabihullah Mujahid said on Twitter. He added that a special unit had arrived on the scene to investigate.

The state-run Bakhtar News Agency reported that at least 43 people had been killed, with more than 140 others wounded.

The so-called "Islamic State" (IS) militant group claimed responsibility for the suicide attack, saying they had targeted the Shiite Hazara ethnic group.

The UN mission to Afghanistan said initial information indicated "more than 100 people killed and injured in a suicide blast inside the mosque."

It represents the deadliest attack since US-led forces left the country at the end of August. 

Shiite minority targeted

A Taliban official cited by the AFP news agency said the explosion was a suicide attack. IS later said in a statement on its Telegram channels that a suicide bomber "detonated an explosive vest amid a crowd".

Another statement said that the perpetrator had been from the Uyghur Muslim minority group that the "Taliban had vowed to expel" from Afghanistan.

Afghanistan has been hit by several deadly bombings in recent weeks, including one at a mosque in Kabul. 

The Taliban leadership — which took power in August amid the withdrawal of US-led foreign troops — has been grappling to curb attacks by the local Islamic State affiliate, known as Islamic State Khorasan. The group has repeatedly targeted Afghanistan's  Shiite community, many of whom belong to the Hazara ethnic minority. Shiites make up roughly 20% of the population in the Sunni-majority country. 

UN 'deeply concerned'

The UN in Afghanistan called Friday's attack "part of a disturbing pattern of violence" and said it was "deeply concerned by reports of very high casualties."

UN refugee chief Filippo Grandi told reporters in Geneva the bombing was "the symptom that the implosion (of Afghanistan) may also translate into renewed insecurity."

"That is also something that we should all be worried about," he said.

nm/fb (AFP, AP, Reuters, dpa)