An Afghan government official said late on Monday that security forces had restored order in a prison, after part of it was besieged and occupied by the "Islamic State," freeing hundreds of inmates. The day-long siege and attack by the IS militants left about 39 people dead, while around 400 prisoners escaped.

Ajmal Omar, a provincial council member, said that at least 10 of the militants who were killed by Afghanistan’s security forces were from the IS. They were thought to be trying to free allied militants from the prison. About 50 people were also wounded in the attack, said Omar.

The conflict began Sunday evening when a suicide car bomb was detonated at the entrance to a prison in Jalalabad, the capital of Nangarhar. An unknown number of assailants then opened fire on the prison's security guards.

A gun battle ensured, lasting through the night and continuing into the day on Monday. Afghan special forces arrived with armored vehicles to provide backup, Nangarthar province officials said. 

High number of inmates escape

The assailants were able to occupy a nearby residential building, complicating attempts by security forces to bring the situation under control, Khogyani said. 

A high number of prisoners escaped amid the chaos, forcing security officials to divert their efforts to recapturing them. 

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The IS affiliate in Afghanistan, known as IS in Khorasan province, claimed responsibility for the attack. It's unclear whether they were trying to free any particular prisoners.

Taliban denies involvement amid ceasefire

The attack came a day after the Afghan intelligence agency killed a senior IS group commander near Jalalabad.

A spokesman for the Taliban said his group had not been involved in the assault on the prison.

"We have a ceasefire and are not involved in any of these attacks anywhere in the country,'' he told news agency AP.

The incident took place during a rare three-day ceasefire between the Taliban and the Afghan government marking the Muslim festival of Eid al-Adha.

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In the past, Nangarthar province was a base for IS militants, until they were pushed out by both Afghan security forces and the Taliban in recent years.

kp, am/msh (AP, dpa, Reuters)