Earlier, five people were injured in two bomb attacks near a school in the same province.
A suicide blast ripped through a crowd of protesters in eastern Afghanistan, killing at least 19 people and leaving over 50 others wounded, an official confirmed.
A delegation from Kabul is heading to the province to probe the attack with a focus on its motive and if there is a connection to the local police commander Bilal Shah, a provincial official said by phone on condition of anonymity because of the sensitivity of the situation.
Relatives and family members of Tuesday's victims have continued blocking the highway, according to local witnesses.
Meantime, spokesman for Nangarhar's provincial government Attaullah Khogiani told Xinhua that 68 people were killed and 165 others injured, saying more details would be available after completion of an investigation.
The spokesperson said that the third explosion took place in police district number three in the provincial capital of Jalalabad, wounding one civilian.
Afghan president Ashraf Ghani strongly condemned the suicide attack against the demonstrators as well as the bomb blasts near schools in Nangarhar.
Afghanistan's parliamentary elections are due in October this year.
The Taliban denied any involvement in the attack.
The death toll from Tuesday's blast soared overnight.
A suicide bomber attacked a protest in the district Mohmand Gift. In January, a Taliban-claimed suicide bombing in the capital Kabul killed at least 103.
In addition to the strikes against the protesters, three schools in the area were also hit.
In the northern province of Sar-e Pul, hundreds of armed men assembled to boost the city's defences as security forces fought to push the Taliban back from the city centre, said Zabihullah Amani, the provincial governor's spokesman.