Noor Ahmad Habibi, deputy spokesman for the governor of Nangarhar province, said a rickshaw rigged with explosives went off among people gathered in the provincial capital, Jalalabad, to mourn a former district chief. He said around 13 other people were wounded.
Habibi said initial reports were that a suicide bomber was behind the attack, but that authorities now believe it was a remotely-detonated explosion.
No one immediately claimed the attack. The Taliban denied any involvement. An Islamic State affiliate is active in Nangarhar province and has targeted officials and security forces in the past.
No one claimed the attack, which took place in a relatively secure part of the country.