A group of suicide bombers attacked a Shiite mosque in southern Afghanistan, triggering explosions that killed dozens of people during crowded Friday prayers.

According to The Associated Press, Hafiz Sayeed, the Taliban's chief for Kandahar's department of culture and information, said 47 people had been killed and at least 70 wounded in the attack.

However, officials have been giving slightly different casualty figures throughout the day.

A local reporter quoted by Reuters news agency said eyewitnesses described three suicide attackers.

One reportedly detonated their device at the door of the mosque, with two more setting off theirs inside the building.

"The firing started after we ended the prayers," a man named Ahmadullah told AFP news agency. "Then two, three explosions took place. We were thrown towards the window. Many people, martyred or wounded, were laying there."

Friday prayers are the busiest congregation of the week, and the building was full of worshippers at the time. At least 15 ambulances were at the scene afterwards, an AFP journalist said.

Taliban special forces have secured the site and have asked people to donate blood to help the victims, Reuters reports.

Video footage showed bodies scattered across bloodstained carpets, with survivors walking around in a daze or crying out in anguish.

The Islamic State group, which like Afghanistan's ruling Taliban is made up of Sunni Muslims, views Shia Muslims as apostates deserving of death.

IS has claimed a number of deadly bombings across the country since the Taliban seized power in August amid the withdrawal of US forces. The group has also targeted Taliban fighters in smaller attacks.