At least seven people, including one assailant, were killed and 20 others wounded after two blasts and ensuing gunshots rocked Jalalabad city, capital of eastern Nangarhar province, on Sunday.
There were two explosions near the city's directorate of finance, Nangarhar provincial governor's spokesman Attaullah Khogyani told AFP, adding that "a number of attackers" had entered the building.
Afghan security forces have struggled to combat the Taliban and ISIS since the U.S. and North Atlantic Treaty Organisation formally concluded their combat role in the country in 2014, shifting to a support and counterterrorism mission.
One of the injured employees, Qaisar, said the assault began around noon, when "a big boom shook our building".
According to Khogyani, at least six ten people, including civilians, workers of the Customs Department, and security personnel lost their lives in the attack.
Uber Unveils Models Of Its Flying Taxis For "Regular People"
Some of those firms appeared alongside Uber at the event with their own concept designs for what the flying taxis could look like. Having four riders fit into each air taxi will definitely make a difference on the cost of each flight.
Most have been in the capital Kabul, but in January gunmen attacked an office of aid group Save the Children in Jalalabad, killing at least five people and wounding 25 in an attack claimed by Islamic State that followed much the same pattern as Sunday's incident. The attackers then stormed the building, trading fire with security officials. "Security forces are in the area chasing and fighting them", he added.
Dozens of people have been killed in voter registration centres in recent weeks.
Violence has escalated across Afghanistan since the announcement of the Taliban's annual spring offensive last month and there have been heightened security fears around preparations for elections in October.
Operation Al Khandaq will target United States forces and "their intelligence agents" as well as their "internal supporters", a Taliban statement said in late April.