The bomber detonated his explosives near the stage where musicians were playing and "all the youths, children and all the people who were there were killed", said Gul Mohammad, another witness.
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.
Trump's comments come after he met with top national security advisers last week at his golf course in Bedminster, New Jersey, to review a US-Taliban peace plan that could end America's longest running war.
The Islamic State (IS) group said it was behind for the attack. It marks the latest ina string of similar attacks in the area, Earlier in the month, three suicide bombers working for the Taliban killed 14 people and injured 145 more.
Ghulam Mohammad, a shopkeeper selling plants, said his two sons and a nephew were among the injured in a blast at the market square.
The Dubai City Wedding Hall is one of many large, brightly lighted venues in Kabul that host elaborate festivities costing upward of tens of thousands of dollars and offer a rare chance for Afghans to celebrate in large groups.
Kabul's huge, brightly lit wedding halls are centers of community life in a city tired of decades of war, with thousands of dollars often spent on a single evening.
Messages of shock poured in on Sunday.
I strongly condemn the inhumane attack on the wedding hall in Kabul last night.
US Ambassador to Afghanistan John Bass called it an act of "extreme depravity".
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Despite the negotiations, the Taliban has continued to engage in attacks. Shiite Muslims are a minority in largely Sunni Afghanistan.
US peace envoy Zalmay Khalilzad took to Twitter to denounce the "heinous attack".
Washington is keen to end its involvement in Afghanistan, where it has spent more than $1tn and Trump has said since the start of his presidency that he wants troops out.
Some US officials want to maintain a counter-terrorism capability in Afghanistan if a withdrawal pact is struck but the Taliban says it wants all foreign to leave.
Graeme Smith, a consultant for the International Crisis Group, said Islamic State is fearful of a peace deal because it is "getting hammered on the battlefield" by both US -backed government forces and the Taliban and "does not want to see its two biggest enemies make peace and join forces against them". He said that will put Afghanistan in a "much stronger position" to defeat the IS affiliate.
Many Afghans fear that terror attacks inside the country will continue, and their pleas for peace - and for details on the talks - have increased in recent days.
Other issues include a cease-fire and intra-Afghan negotiations on the country's future. "The Taliban have laid the foundation for such brutal killings".
"Taliban can not absolve themselves of blame, for they provide platform for terrorists", President Ashraf Ghani said Sunday on Twitter, declaring a day of mourning and calling the attack "inhumane".
Under the expected deal, the Taliban, in exchange for a US commitment to withdraw, would guarantee that Afghanistan would not be a sanctuary for militants to expand and plot new attacks.
The two sides appear to be closing in on an agreement in which the USA would withdraw its forces in return for a pledge from the Taliban to keep the country from being used as a launch pad for global attacks.