Two intelligence agents and 10 civilians were killed in Jalalabad, authorities have confirmed, with children among the victims.
Five others were injured in the bombing, which targeted the intelligence service, according to Attaullah Khogyani, spokesman for the provincial governor.
Officials said the attacker, who was on foot, detonated the device near a petrol station.
Witnesses spoke of seeing a “big ball of fire” which threw people in the air, according to reports.
“Most of the victims were children who were working in a car wash close to the suicide bombing site,” said Sohrab Qaderi, a member of the provincial council.
Isis claimed responsibility for the attack, in a statement on their Amaq news agency.
Eight cars were also destroyed in the explosion and several nearby shops damaged.
Meanwhile, in the western Farah province, Taliban fighters attacked police checkpoints on Monday evening, killing three police officers and wounding four others, said Mohammad Naser Mehri, spokesman for the provincial governor.
At least five Taliban fighters were killed and seven more wounded in the gun fight in the Bala Buluk district, he added.
Earlier this month, another suicide bombing in Jalalabad claimed the lives of at least 19 people, most of whom were Sikhs and Hindus. Isis claimed responsibility for the attack.
Agencies contributed to this report.
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