At least three bombs exploded outside a jail compound in the eastern Afghan city of Jalalabad on Sunday, officials said.
Sohrab Qaderi, a provincial council member in Jalalabad, said a huge car bomb explosion was followed by at least two smaller bomb blasts outside a government-run prison, and that police then fought attackers who took up position near the prison.
“At least 20 people were injured in the ongoing clashes,” Qaderi said.
A Taliban spokesman said the Islamist militant group was not responsible for the attack.
On the third and final day of a ceasefire between the Taliban and Afghan government, hundreds of Taliban prisoners were released in an attempt to make a final push for intra-Afghan peace talks.
President Ashraf Ghani and the Taliban have both indicated that long-delayed negotiations could begin immediately after the Eid al-Adh festival.
The Taliban says it has freed all 1,000 Afghan prisoners it had pledged to release in a deal with the United States.