The explosion rocked the area just before 11.30am on Tuesday, residents reported.
Officials have also confirmed that security forces have arrived in the area.
One eyewitness told TOLOnews that at least three gunmen stormed the building after an explosion.
Another eyewitness said he heard at least two explosions before fleeing the area.
This comes just three days after a complex attack on a midwife training center in Jalalabad.
This attack lasted almost six hours – and claimed the lives of two people.
On Monday Nangarhar provincial health officials also raised concerns over the sharp increase in civilian deaths in the past three months.
They said 160 people had been killed and over 490 wounded in the province in serious security incidents in this time.
Provincial council members also raised concerns and said they were extremely worried about the security situation in the city.
But there has been a string of deadly attacks in the past few months, including the suicide bombing near the governor’s office on the third day of Eid al-Fitr, the attack on the education department and this week’s complex attack on a midwife training center that lasted over five hours.
Among a long list of attacks in recent months, these included the July 1 suicide bombing which killed at least 19 people, mostly from Afghanistan’s Sikh community.
On June 17, eighteen 18 people were killed – also in a suicide bombing.
On July 10, another ten people were killed in a suicide bombing – on a police checkpoint.