It was the latest deadly violence to strike Afghanistan as militant groups step up attacks and US-backed Afghan forces intensify air strikes and ground offensives.
At least seven people, including an assailant, were killed and 20 others wounded after two blasts and ensuing gunshots rocked Jalalabad city on Sunday.
At least three explosions were heard at the beginning of what authorities believe to be a coordinated attack, Nangarhar provincial governor spokesman Attahullah Khogyani said.
Sohrab Qaderi, a member of the provincial council, told Reuters that at least four militants, armed with rocket-propelled grenades and machine guns, are still fighting the police.
At least four have died in in an attack in Jalalabad.
No group including the Taliban immediately claimed responsibility for the attack. More explosions were heard later coming from inside the building, the official added.
At the same time, Taliban fighters have stepped up the pressure on government forces across the country, from Baghlan province in the north, where they seized a district centre last week, to Farah in the southwest or Ghazni, south of Kabul.
April saw a series of attacks across the country targeting voter registration centers as the country gears up for long-delayed legislative elections due in October.