Provincial governor's spokesperson Attaullah Khogyanai told Efe news that a suicide bomber blew himself up outside the building that houses the office used for the distribution of electronic identity cards.
An unknown number of gunmen later entered the complex, surrounded by residential houses and markets places.
Khogyanai said that security forces cordoned off the area for clearance operations and rescued the employees trapped inside the building.
He said 12 employees were rescued as "clearance operation continued while security forces were trying to eliminate the attackers".
Zahir Adil, a spokesperson for Nangarhar health department, said that "over 10 injured persons were evacuated to a regional hospital".
"The number of injured persons might rise as the evacuation of victims was still under way and the attack was going on," Adil said.
No insurgent group immediately claimed responsibility for the attack on the office that distributes new electronic national IDs to replace the old hand-written election cards.
The assault comes a day after two attacks claimed by the Taliban killed at least 48 people in the war-torn country.
There has been a surge in militant attacks in Afghanistan in the past few weeks ahead of the presidential elections set for September 28.
Peace negotiations between the US and the Taliban were called off amid rising violence in the country.
US President Donald Trump cited the surge in violence for cancelling peace talks that would have ended America's longest war and secured the withdrawal of foreign troops from Afghanistan.
The US and the Taliban negotiators were on the verge of signing an accord after agreeing in principle to a draft peace deal after more than a year of negotiations in Qatar. But Trump said the talks were "dead" after the death of an American soldier in a Taliban attack earlier this month.
( With inputs from IANS )