A second night of clashes and gunbattles between the army and protesters in Yemen's main southern city of Aden left seven people wounded, three of them soldiers, witnesses and officials said.
Security forces used tear gas and gun fire to disperse the protesters who took to the streets until late Wednesday night in several Aden neighborhoods, the witnesses said.
Chanting pro-secessionist slogans, the protesters set car tyres ablaze, blocked several roads and wounded a soldier when they hurled stones at the security forces, said one witness.
In Al-Saada neighborhood, two soldiers and a civilian were wounded in gunbattles, a security official said.
During the protests, security forces arrested dozens of members of the Southern Movement, an activist, Ahmed al-Zubeiri, told AFP.
Dozens of other protesters were rounded up during similar clashes in Aden on Tuesday, witnesses said.
The main leaders of the Southern Movement, Ali Salem al-Baid, who is in exile, and Hassan Baoum -- freed by the authorities early this month -- had called for Tuesday to be a "day of rage" to protest against the government in Sanaa.
South Yemen was independent from 1967, when Britain withdrew from Aden, until the region united with the north in 1990.
The south attempted to secede in 1994, sparking a short-lived civil war that ended with it being overrun by northern troops
Many residents of south Yemen complain of discrimination by the Sanaa government in the distribution of resources, sparking frequent protests, with calls ranging from economic and social improvements to full independence.
2010 death toll
Battles against al-Qaeda jihadists and southern separatists killed 178 members of Yemen's security forces last year, the interior ministry announced on Thursday.
A total of "1,030 members of the security forces were killed and wounded in 2010" while "defending security and stability and confronting terrorism, outlaws, and crime," a ministry statement said, giving a figure of 178 killed.
The statement referred to clashes with members of al-Qaeda in the Arabian Peninsula (AQAP), which is regrouping in the ancestral homeland of Osama bin Laden, and the separatist Southern Movement, spearheading opposition to the government.
Sanaa is also battling a sporadic Shiite rebellion in the north of the poverty-stricken country, but the statement did not say how many security force members died in the fight.