Four soldiers and 2 gunmen were injured when saboteurs attacked a security checkpoint in Yemen's southern Dhale province, local sources said on Thursday.

The armed saboteurs threw bombs on a security patrol and an armoured car at the checkpoint, destroying them and injuring the four soldiers, they said.

Two armed people were also wounded in the attack, a security source said.

The local sources also said that armed people, believed to be separatists, closed Sana'a-Aden road in Khawber Sanah area, preventing cars from passing.

The move triggered clashes between them and the security forces, they said.

The developments coincided with rallies in some southern cities when demonstrators protested against the detention of separatist leader Hassan Ba'oum, holding the government responsible for his safety.

Protesters carried the pictures of Ba'oum and after-reunification vice president Ali Salim Al-Beidh Vice President Ali Salim Al-Beidh, who fled the country after the 1994 separation war, and victims of the separatist movement, Al-Harak, as well as flag of the People's Democratic Republic of Yemen.