* 20 injured in attack on Jalalabad jail – local official

* Islamic State claims responsibility

* Coincides with final day of truce between govt, Taliban

By Rupam Jain

Sohrab Qaderi, a provincial council member, said a huge car bomb explosion was followed by at least two smaller blasts outside the government-run prison, and that police then fought attackers who had taken up positions nearby.

Islamic State’s Amaq news agency quoted a military source as saying its fighters had carried out Sunday’s attack but gave no further details. There was no independent confirmation that the militant group was responsible.

“At least three people were dead and 25 were injured in the ongoing clashes,” Qaderi said. More than 50 prisoner escaped, and the death toll could rise, he added.

The assault happened on the third and final day of a ceasefire between the Afghan government and the Taliban, when hundreds of Taliban prisoners were released in an attempt to make a final push for intra-Afghan peace talks.

The Taliban was not responsible for the attack, a spokesman for the Islamist group said.

President Ashraf Ghani and the Taliban have both indicated that long-delayed negotiations could begin immediately after the Eid al-Adha festival, which took place in Kabul on Thursday.

The Taliban says it has freed all 1,000 Afghan prisoners it had pledged to release in a deal with the United States.

(Reporting by Ahmed Sultan in Jalalabad, Abdul Qadir Sediqi in Kabul and Ahmed Tolba in Cairo; Writing by Rupam Jain and Timothy Heritage; Editing by John Stonestreet)