Attaullah Khogyani, a spokesman for the Nangarhar governor, told RFE/RL that at least 54 others were also injured in the explosion.
An Afghan official says a suicide bomber blew himself up in the middle of a gathering of mostly Taliban members who were celebrating a three-day cease-fire outside the Nangarhar provincial capital of Jalalabad, killing 11 and wounding another 12 people. The bombing killed 26 people and another 41 were wounded, a lot of them believed to be Taliban fighters who had gathered to celebrate a three-day cease fire marking the Islamic holiday of Eid al-Fitr, a police official said.
There was no immediate claim of responsibility.
Dozens of unarmed Taliban militants had earlier entered the Afghan capital and other cities to celebrate the end of the Ramadan fasting season.
"President Ghani's latest decision to offer an extension of the ceasefire is another courageous step to make way for peace negotiations and we call on the Taliban to reciprocate", said the EU's foreign policy chief Federica Mogherini in a statement.
The Taliban announced a ceasefire for the first three days of Eid, which started Friday, promising not to attack Afghan security forces for the first time since the 2001 U.S. invasion.
"The Afghan people this year are spending the Eid holidays with their families with renewed hope of peace".
Provincial police spokesman Shahpur Ahmadzai told The Associated Press that the Taliban were unarmed and no one was allowed into the city with weapons.
The two warring sides took selfies with each other as the ceasefire across Afghanistan held for the second day of Eid.
"I am here to offer greetings to our brothers in the police and army", Taliban commander Baba said.
In the meantime, the USA embassy said in a statement that the United States extends its best wishes to the people of Afghanistan in celebration of Eid al-Fitr.
Russian Federation thrash Saudi Arabia to launch World Cup in style
Aleksandar Golovin assisted two goals before netting a sweet free-kick in extra time to cap a confident first win. Both teams surpassed that in Sochi, where they played to a 3-3 tie that fans will be talking about for years.
At an impromptu meeting beside a highway outside Kabul, Interior Minister Wais Barmak met with a contingent of Taliban leaders travelling from Wardak province to the capital.
The Afghan government is under heavy pressure to restore security and take back territory controlled by a number of insurgent groups, including the Taliban and IS.
The ceasefire followed large peace rallies around the country and came as 80 citizens continued a 600km-long peace march from Lashkar Gah to Kabul. Their weapons would be returned when they leave, he said.
'We are all just so exhausted of war, ' he said.
"They (security forces) are all our brothers".
The unusual bonhomie between the two sides also came as Ghani confirmed that Pakistani Taliban chief Maulana Fazlullah had been killed in a U.S. drone strike.
A Taliban fighter on a motorbike carrying the Afghan and Taliban flags welcomed the ceasefire, but said long-lasting peace would only be achieved if United States forces left the country.
For many Afghans it has been first glimpse of peace in their lifetime. "I can see Taliban walking around among ordinary people". For the first time, we felt safe.
They added: "Our operations will continue against them, we will attack them wherever we see them". In some districts of the eastern city of Jalalabad, civilians were offering dry fruit, traditional candies and ice cream to Taliban militants.
The Taliban, wearing traditional headgear and many with sunglasses, entered Kabul through gates in the south and southeast.