Security forces shot dead two southern activists during a protest on Thursday in the town of Daleh against Yemen's presidential election to be held later this month, witnesses and activists said.
"Southerners wake up, no more elections," chanted the protesters referring to a referendum-like election in which Vice President Abdrabuh Mansur Hadi stands as sole candidate based on a Gulf-brokered deal signed by departing President Ali Abdullah Saleh in November.
"Revolt, revolt, south," they shouted, waving the flag of the formerly independent South Yemen, witnesses said.
"Clashes erupted and security forces opened fire, killing two activists," said one witness.
The protesters marched towards the headquarters of the electoral committee in Daleh in an attempt to drive its members out of the city when security forces opened fire, witnesses said.
Activists from the separatist Southern Movement who say the February 21 election fails to meet their aspirations for autonomy or southern independence, confirmed the deaths.
Some factions of the movement have been campaigning for a boycott of the election, while others who follow the Yemen Socialist Party's former leader Ali Salem al-Baidh openly call for preventing the poll from taking place at all.
A similar incident took place on February 5 when southern activists overran a police station in Hadramut province and two of them were killed when security forces intervened to evacuate the station.
Signup to our newsletter and follow us on Facebook and Twitter!
Separately, in Huta, another southern city, unknown gunmen shot dead a police officer on Thursday.
"Two gunmen on a motorbike shot dead the head of the criminal investigation unit in Tubn (Lahij province), Colonel Mohsen al-Khudr," a police official told AFP, adding that the assailants fled.
Residents in the formerly independent southern region complain of discrimination by the Sanaa government in the distribution of resources since the north-south union in 1990.
The south broke away again in 1994, sparking a brief civil war that ended with the region overrun by northern troops.
Hadi, himself a southerner, is the sole candidate in the election to succeed veteran strongman Saleh who is standing down after more than three decades in power following several months of deadly protests.
On Tuesday, he launched his campaign for the presidential poll.
Saleh has been in New York since late last month to receive medical treatment for wounds suffered in a June bombing at the presidential palace in Sanaa.
US officials have said he will not return to Yemen until after the election but state news agency Saba reported on Tuesday that Saleh had told visitors he would "participate" in the poll.