FIFA president Gianni Infantino offered his condolences on Saturday after the death toll from a suicide bombing at a football stadium in Iraq rose to 41.
Iraqi officials said another 105 people were wounded in the attack that was claimed by the Islamic State group.
The bombing took place on Friday during a match in the small stadium in the city of Iskanderiyah, 30 miles (50 kilometers) from the capital, Baghdad.
Infantino said in a statement: "I'm shocked and terribly saddened to have learnt about the awful tragedy, which occurred yesterday at a football game in Iskanderiyah, Iraq.
Around the world, football unites people. It is a very sad day when people, going to a match together, become the victims of such violence.
On behalf of FIFA and the global football community, I would like to extend our deepest condolences to the victims' families.
Our thoughts are with all those affected by this tragedy and all our football friends in Iraq."
U.N. Secretary-General Ban Ki-moon also offered his condolences on Saturday, saying "the international community stands with Iraqis in horror and outrage."
Speaking during an official visit to Iraq, Ban said that the battle against the group must comply with international law, noting continued reports of arbitrary arrests and killings in IS-liberated areas.
The extremist group has lost ground in recent months in Iraq and Syria, but has struck back with a series of large attacks targeting civilians. IS claimed this week's attacks in Brussels, which killed 31 people.
Information from The Associated Press was used in this report.