The attacks continued into Monday involving hundreds of prisoners. Since the Afghan prison attack began, there are reports of 21 casualties from overnight fighting.
Another 43 people were wounded in the attack that began late Sunday during which an Islamic State suicide bomber slammed an explosive-laden vehicle into the prison entrance.
More assailants opened fire.
Three attackers have been killed so far but the battle continued Monday with sporadic gunfire still coming from the prison grounds, said Attaullah Khogyani, a spokesman for the governor of Nangarhar province.
Some of the dead were prisoners, said Khogyani. as well as civilians, prison guards, and Afghan security personnel.
The prison assault struck Jalalabad, Nangarhar's provincial capital some 115 kilometers (70 miles) east of the capital, Kabul.
The Islamic State group's affiliate in Afghanistan, known as IS in Khorasan province, claimed responsibility for the attack. The affiliate is headquartered in Nangarhar province.
The motive of the attack wasn't immediately clear.
However, some prisoners have escaped during the fighting, said another provincial official, who spoke on condition of anonymity because he was not authorized to speak to journalists.