At least four Yemenis, including a policeman, have been killed in two days of clashes between police and anti-government protesters.
Another 13 people were wounded in the exchanges of fire on Saturday and Sunday, which followed demonstrations in the south of the nation against the Sanaa government, medics and police said.
In one clash on Sunday in the village of Labouss, in Lahij province, a policeman and demonstrator were killed.
Another protester was killed in Dali, north of the port of Aden, in south Yemen, when police used firearms to disperse the crowd.
"One protester, Tufiq al-Jaadi, died while being operated on in hospital. He was hit by a bullet," medical sources said of the Dali incident.
In al-Eind village, near Labouss, a third protester was killed in similar circumstances.
Violence also occurred in a hospital when police attempted to arrest a demonstrator, causing injuries to two people.
One demonstrator died in clashes with police on Saturday in the village of Ashehir, in the southeastern Hadramut region.
Aden is the former capital of South Yemen, which was united with the north of the country in 1990.
Protesters carried banners with anti-government messages and posters of Ali Nasser Mohammed, the former president of South Yemen.
The death toll since protests started in the south in late April is now 16, including five security personnel.
Socialists, who formerly ruled the south, previously tried to gain secession in 1994, igniting a two-month civil war before the movement was crushed by forces loyal to the government.
Some southerners want independence because of alleged discrimination and neglect.
However, President Ali Abdullah Saleh has give warning that the nation could split up into several entities.