Officials say bomber targeted volleyball tournament match attended by large crowd in province bordering Pakistan.
A suicide bomber has killed dozens of people in an attack on a volleyball match in Afghanistan's east, officials say.
Mukhles Afghan, spokesman for the governor of Paktika province, bordering Pakistan, said the attack happened late on Sunday afternoon during an inter-district tournament match attended by a large crowd in the Yahya Khel district district.
Officials said at least 49 people were dead and about 50 more were wounded in the attack, adding that most casualties were civilian.
The suicide bomber was on foot in the crowd, Afghan said.
International Olympic Committee President Thomas Bach condemned the "cowardly" attack.
"It is an attack on sport itself and on the positive values it can bring to help build strong communities and foster peace and reconciliation around the world," he said in a statement.
Al Jazeera’s Charles Stratford, reporting from Kabul, said the toll was expected to rise as the target was a well-attended match.
No group has claimed responsibility yet, but Paktika has been targeted by the Taliban before, he said.
The Taliban and other fighters have mounted multiple suicide attacks and assassinations in Afghanistan this year, as foreign forces continue to withdraw after 13 years of war.
Pakistan has condemned the deadly attack. "No cause justifies such acts of terrorism and taking of innocent lives," its foreign ministry said in a statement.
Sunday's attack is one of the deadliest so far this year, a time when attacks are escalating following a controversy-marred election and the inauguration of President Ashraf Ghani in September.
Afghanistan's parliament approved agreements on Sunday with the US and NATO allowing international troops to remain in the country past the end of this year.
According to the deals, about 12,000 international troops will remain in Afghanistan next year to train and support Afghanistan's security forces.
Ghani's first act after becoming president was to sign the agreements, which are opposed by the Taliban and other armed groups.
US President Barack Obama wants all American troops to be out of Afghanistan by the end of 2016, as his presidency draws to an end.
Source: Al Jazeera and agencies