Another 57 were wounded in the blast in Nangarhar province, where people had blocked a highway in protest over the appointment of a local police chief, the provincial governor's spokesperson Ataullah Khogyani said.
Burqa-clad suicide bombers kill at least 29 inside Afghan a mosque
The attack came hours after a double bombing in front of a girls' school in the provincial capital of Jalalabad killed a boy and wounded four others.
The first explosion happened in front of Malika Omaira girls' school at around 8:30am, Khogyani told AFP earlier.
A second bomb went off as students from a neighbouring boys' school and locals gathered at the scene, he added.
There has been no claim of responsibility for any of the attacks, but the Taliban and the Islamic State group are active in Nangarhar, which borders Pakistan.
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