Gunmen attacked an office of Yemen's electoral committee in a southern province, a local official said on Sunday, in the latest sign of opposition to a presidential election next month.
The official told Reuters the gunmen, armed with machine guns and rocket propelled grenades, wounded two soldiers who were guarding the building in Dalea before fleeing the scene.
The government, weakened by a year of protests against outgoing President Ali Abdallah Saleh, faces challenges from al Qaeda-linked militants who have seized territory in the south and separatists who want to revive a southern socialist state that existed before Saleh united it with the north in 1990.
Thousands protested against the election on Friday, some burning their voting cards and raising the flag of the old South Yemen.
"The people of the south reject the elections completely," separatist leader Nasser al-Khubbagi told Reuters on Friday. "Holding them is an affirmation of the (northern) occupation and legitimizes its continuation in the south."
Separatist leaders have vowed that the resistance to the election would be non-violent in the south, home to many of Yemen's oil facilities and where many say northerners have seized resources and discriminated against them.
The Sanaa government says the south's economic woes are shared by the north.
The United States and Saudi Arabia fear Islamist militants are exploiting the turmoil to strengthen their foothold in the south, near oil shipping routes through the Red Sea.
Saleh, who travelled to the United States on Saturday for treatment for wounds sustained in an assassination attempt last year, has handed over power to his deputy after months of protests against his rule, paving the way for an early presidential election next month.
Northern Shi'ite Muslims rebels known as Houthis, who have been left out of the deal to ease Saleh out of power, have also said they planned to boycott the February 21 vote.