JOIN USA suicide attacker blew himself up at a funeral in eastern Afghanistan on Sunday, killing at least 18 mourners and wounding another 13, officials said, capping a deadly year for civilians.
There was no immediate claim of responsiblity for the blast which authorities initially said was caused by a suicide attacker but now believe was triggered by explosives attached to a motorcycle.
The Taliban said on Twitter they had nothing to do with the incident -- the latest violence to claim the lives of civilians in the war-torn country.
"The explosion was caused by a motorcycle bomb our investigation has concluded," Nangarhar governor spokesman Attaullah Khogyani said.
The governor's office put the death toll from the attack near the provincial capital Jalalabad at 18, with 13 wounded.
The explosion happened during the funeral ceremony for a former governor of Haska Mina district who died recently of natural causes, a statement from the governor's office said.
The twisted wreckage of a motorcycle - a popular mode of transport in impoverished Afghanistan - lay in the dirt at the cemetery.
While the Taliban is still responsible for the majority of attacks and casualties across Afghanistan, Islamic State militants have been on a rampage this month.
More than 8,000 civilians were killed or wounded in conflict-related violence in the first nine months of this year, according to data compiled by the UN Assistance Mission in Afghanistan.