The hours-long attack in Jalalabad began early Wednesday when two suicide bombers detonated explosives at the gate of the compound, allowing three others to enter the area where they went on a killing spree, provincial spokesman Attaullah Khogyani told AFP.
Security forces rushed to the city, which is the capital of Nangarhar province.
"Sixteen employees of the company have been killed and nine more injured," the spokesman said, adding the attack began at 5:00 am local time.
A spokesman with Afghanistan's interior ministry confirmed the account and toll.
"All five attackers have been killed by security forces," Khogyani added.
Nangarhar provincial council member Ajmal Omar put the death toll slightly higher, saying 18 people had been killed with three of the nine injured in a critical condition.
Health workers pored over the injured in a nearby hospital, with bloody bandages covering their wounds.
Spokesman Khogyani added that a clearance operation was ongoing with security defusing two suicide vests, a car bomb, and multiple mines planted by the attackers.
"Armed suicide bombers attacked and managed to enter the building of a private construction company early this morning," said Nangarhar Provincial council member Zabihullah Zmarai.
No group has claimed responsibility for the attack, but both the Islamic State group and the Taliban are active in Nangarhar province.
The Taliban later denied involvement.
"The Jalalabad attack has nothing to do with us," Taliban spokesman Zabihullah Mujahid told AFP.
Source : Afghan Voice Agency(AVA)