Interior ministry spokesman said the blast occurred in a west Kabul wedding hall. (Reuters)

A suicide bomber killed more than 60 people and wounded scores, including women and children, as they celebrated a wedding in the Afghan capital, authorities said Sunday, the deadliest attack in Kabul in recent months.

The blast, which took place late Saturday in the city's west, came as Washington and the Taliban are in the final stages of a deal to reduce the US military presence in Afghanistan.

The Taliban denied any involvement in the attack.

Interior ministry spokesman Nasrat Rahimi said at least 63 people had been killed and 182 injured. "Among the wounded are women and children," Rahimi said. Earlier he stated that the blast was caused by a suicide bomber.

Afghan weddings are epic and vibrant affairs, with hundreds or often thousands of guests celebrating for hours inside industrial-scale wedding halls where the men are usually segregated from the women and children.

In the aftermath of Saturday's attack images from inside the hall showed blood-stained bodies on the ground along with pieces of flesh and torn clothes, hats, sandals and bottles of mineral water.

The wedding was believed to be a Shia gathering. Shia Muslims are frequently targeted in Sunni-majority Afghanistan, particularly by the so-called Islamic State group, which is also active in Kabul but did not immediately issue any claim of responsibility.

Mohammad Farhag, who had been at the wedding, told AFP he had been in the women's section when he heard a huge blast in the men's area.

"Everyone ran outside shouting and crying," he said.

"For about 20 minutes the hall was full of smoke. Almost everyone in the men's section is either dead or wounded."

Two hours after the blast, he said bodies were still being removed from the hall.

A mobile phone video which swiftly went viral shortly after the attack showed one man outside the hall with bloodstains on his clothes, his voice breaking as he explained he was searching for his brothers.

One guest who spoke to Tolo News said some 1,200 people had been invited.

The attack sent a wave of grief through a city grimly accustomed to atrocities.

"This heinous and inhumane attack is indeed a crime against humanity," tweeted Afghanistan's chief executive Abdullah Abdullah.

"This was a wedding. Imagine two family groups gathered for a celebration now bearing such unimaginable, paralyzing loss," tweeted analyst Ahmad Shuja.

Withdrawal deal expected

Insurgents have periodically struck Afghan weddings, which are seen as easy targets because they frequently lack rigorous security precautions.

On July 12, at least six people were killed when a suicide bomber attacked a wedding ceremony in the eastern Afghan province of Nangarhar. IS, which has a growing footprint in the region, claimed the blast.

Expectations are rising for a deal in which the United States would start withdrawing its approximately 14,000 soldiers from Afghanistan after a two-decade war that has turned into a stalemate.

In return, the Taliban would commit to various security guarantees, including a pledge that the Islamist hardliners who long harboured Al-Qaeda would not allow Afghanistan to once again become a jihadist safe haven.

The deal would allow America to exit its longest war, but few believe it will bring peace immediately to Afghanistan.

Many Afghans fear the Taliban could return to some form of power, eroding hard-won rights for women in particular, or the country descend further into a brutal civil war.

On Friday, Ahmadullah Azkhundzada, brother of Afghan Taliban leader Haibatullah Akhundzada, was among four people killed in a blast at a mosque in Pakistan's southwestern Balochistan, a senior official with the provincial government said.