Armed militants have renewed attacks against government buildings near the southern Yemeni town of Houta, which they had assaulted on Wednesday.
Residents said the attackers in Thursday's raid briefly took over a security headquarters and council offices in Masameer, which is close to Houta, before retreating.
Also Thursday, Yemen's Defense Ministry said two people were killed after "terrorists" fired mortar rounds in the city of Zinjibar, most of whose population has fled to the port of Aden. Militants seized Zinjibar and another southern city in May.
Meanwhile, Yemeni authorities say they arrested 10 suspected al-Qaida suspects who had infiltrated Aden from Abyan province. Abyan is an al-Qaida stronghold.
On Wednesday, the Islamist group Ansar al-Sharia, or Supporters of Sharia (Islamic law), attacked Houta before dawn, briefly seizing key areas of the provincial capital and battling with government security forces.
The assaults have raised concerns about increased violence from Islamist groups in Yemen's restive south amid nationwide anti-government protests and the absence of embattled President Ali Abdullah Saleh.
President Saleh is recuperating in Saudi Arabia from injuries sustained in a bomb attack on his presidential compound earlier this month.
Yemeni state media quoted Saleh Thursday as telling Bahrain's king by telephone that his health is improving and expressing confidence that Yemen is capable of overcoming the current crisis.
Anti-government demonstrators in Yemen want Saleh to step down. Protesters have been calling for a transitional council that excludes members of the current government.
Some information for this report was provided by AFP and Reuters.