A SUICIDE bomber has struck at a Shiite mosque in the Afghan capital Kabul, killing 32 people, the UN office said.
The bomber walked into the Shiite mosque in western Kabul where he detonated his explosives among the crowd of worshippers, Afghan police said.
It is the second large-scale attack targeting minority Shiites in Kabul in just over a month.
No group immediately claimed responsibility for the attack, though Sunni extremists such as the Taliban and Islamic State militants, who view Shiites as heretics and apostates, frequently target Shiite mosques and public gatherings.
The United Nations Assistance Mission in Afghanistan (UNAMA) said the explosion also wounded more than 50 people, many of them children.
Earlier in the day Afghan authorities said at least 28 people were killed and 48 wounded.
"This appalling attack on worshippers is an atrocity," a statement from Pernille Kardel, the secretary-general's deputy special representative for Afghanistan, said.
"UNAMA expresses its revulsion at this latest effort by extremists to stoke sectarian violence in Afghanistan."
Monday's bombing hit during a prayers ceremony commemorating 40 days since the anniversary of the death of Imam Hussein, the grandson of the Prophet Mohammed.
The ceremony is known as Arbaeen, meaning 40 in Arabic. Hussein is a revered Shiite martyr who was killed in 680 AD in the city of Karbala in present-day Iraq.
In early October militants attacked another Shiite ceremony at a shrine in Kabul, commemorating the anniversary of Hussein's actual death.
That attack killed 17 people, mostly worshippers but also several policemen.
A day later, a similar attack struck Shiites in the city of Mazer-e Sharif in northern Balkh province, killing at least 14 people.
The IS affiliate in Afghanistan claimed responsibility for one of those two attacks, the UN statement said.
Faredoon Obiadi, head of the criminal investigation department for the Kabul police, said the attacker in Monday's bombing walked into the Baqir-ul Ulom mosque during prayers.
He mingled among the crowd on the first floor of the two-storey building where he detonated his explosives, Mr Obiadi said.
"Suddenly, a huge explosion happened, then everything went dark," 50-year-old Ewaz Ali, who was inside the mosque but suffered only minor wounds, said.
Ms Kardel, from the UNAMA, added in her statement that "religious and ethnic tolerance are values the Afghan people hold strong".
"I urge the Afghan authorities to do everything possible to defend Afghans of all faiths," she said.
US General John W Nicholson, commander of the US-led Resolute Support Mission in Afghanistan, condemned the bombing yesterday.
"On behalf of the men and women of Resolute Support, we offer our condolences to the families of the innocent men, women and children killed and wounded in today's attack," Gen Nicholson said.
"We will continue to stand with our Afghan partners and do everything possible to secure a peaceful, stable Afghanistan."
Shiites in Afghanistan make up an estimated 15 per cent of the country's population of around 30 million.
Their public celebrations and commemorations were largely banned during the five years when the Taliban controlled the country.
But Afghanistan's Shiites have become more public since the extremists were overthrown in the US invasion of 2001.
In July this year a suicide bomber targeted ethic Hazaras, who are mostly Shiite, as they marched through central Kabul to protest against discrimination.
At least 80 people were killed and more than 200 were wounded in that attack, which was claimed by IS.
In 2011 at least 54 people were killed when a suicide bomber detonated his explosives at a Shiite shrine in Kabul where hundreds of people had gathered to mark the Ashoura.
