At least six people were killed when militants detonated bombs and stormed a government building in the eastern Afghan city of Jalalabad on Sunday, reported TOLO news.
Officials said a suicide bomber detonated explosives outside Jalalabad's customs finance department before other insurgents stormed the building. An eyewitness said four explosions have been heard in the area.
No group including the Taliban immediately claimed responsibility for the attack.
Jalalabad is the capital of restive Nangarhar, which borders Pakistan. Some areas of the province are a stronghold of the Islamic State group but Taliban fighters are also active there.
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.
The Taliban have rejected growing calls to accept President Ashraf Ghani's offer of talks to end the 16-year conflict.