KUNDUZ, Afghanistan: A blast ripped through a mosque during Friday prayers in northern Afghanistan killing 33 people and wounding 43 more, a Taliban spokesman said, just a day after the Islamic State group claimed two separate deadly attacks.

Since Taliban fighters seized control of Afghanistan last year after ousting the US-backed government, the number of bombings has fallen but the IS has continued with attacks against targets they see as heretical.

Taliban spokesman Zabihullah Mujahid tweeted that children were among the 33 dead in the blast at a mosque in the northern province of Kunduz.

"We condemn this crime... and express our deepest sympathies to the bereaved," he said.

Images posted to social media which could not be immediately verified showed holes blown through the walls of the Mawlavi Sikandar mosque, popular with Sufis, north of Kunduz city.

Militant groups such as IS bear a deep hatred for Sufis who they view as heretics and accuse them of polytheism -- the greatest sin in Islam -- for seeking the intercession of dead saints.

"The sight at the mosque was horrifying. All those who were worshipping inside the mosque were either injured or killed," said Mohammad Esah, who owns a shop near the mosque.

A nurse at a nearby district hospital told AFP over the phone that between 30 to 40 casualties had been admitted from the blast.

Multiple bomb blasts

It comes a day after the Islamic State group claimed a bomb attack at a Shiite mosque in the northern city of Mazar-i-Sharif that killed at least 12 worshippers and left 58 people injured.

They also claimed a separate attack in Kunduz city on Thursday, which killed four people and wounded 18.

Earlier on Friday the Taliban authorities said they had arrested the IS "mastermind" of Thursday's bombing at the mosque in Mazar-i-Sharif.

Taliban officials insist their forces have defeated IS, but analysts say the militant group is a key security challenge.