Iraq has buried the victims of a suicide attack in a football match in the city of Iskandariya that killed at least 32 people.
Many of the dead were young boys who were in a trophy ceremony hit by the bomber, himself said to be a teenager.
So-called Islamic State (IS) said it carried out the attack.
IS is a mainly Sunni group which controls large swathes of northern and western Iraq, and has attacked numerous Shia targets in the country.
UN Secretary General Ban Ki-moon, in Iraq for talks with the government, expressed his condolences to the families of the victims.
"I would like to take this opportunity to express my deepest condolences to the people and government of Iraq, and particularly those members of the families affected by terrorist attacks yesterday," he told reporters in Baghdad.
Mr Ban urged Iraqi leaders to step up reconciliation efforts between Shias and Sunnis in order to defeat IS.
Friday's attack happened in Iskandariya, a mainly Shia town 40km (25 miles) south of the capital, Baghdad.
Video posted on social media showed the moment of the blast, as an official was speaking in front of a crowd of dozens of people, including the young players.
The footage cuts off with a big flash of yellow light. It then shows the chaos and screaming of people fleeing the area.
A medical official said 17 of the dead were boys aged between 10 and 16, AFP news agency reported.