A suicide bomber in southern Yemen gravely wounded three members of the separatist Southern Movement on Friday in an attack in Lahij province, the group and a local official said.
The bomber detonated an explosives belt as activists' cars headed for the port of Aden for a demonstration on Saturday marking the independence of the former South Yemen.
A Southern Movement source said the attack took place in Al-Askariya district of Lahij.
The bomber was killed "and three members of the Southern Movement were gravely wounded and evacuated towards Aden to be hospitalised", the source said.
A local official confirmed to AFP that three people had been seriously wounded in the attack, for which there was no immediate claim of responsibility.
The southern question has been a major stumbling-block in a Yemeni national dialogue launched in March, with hardline factions of the Southern Movement demanding secession and boycotting the talks.
Secessionists have called for a major rally to be held in Aden on Saturday in support of their demands, activists say.