At least ten separatists and three soldiers were injured in clashes in southern Yemen on Saturday, an official said, as President Ali Abdullah Saleh's government steps up a crackdown on southern secessionists.
Escalating violence between troops and separatists in Yemen's southern provinces has left several dead on both sides in recent weeks.
The soldiers were attempting to arrest suspects in the killing of a local intelligence official in the province of Dalea, the government official told Reuters. He said seven separatist leaders were arrested in the operation.
Witnesses and southern media said Yemeni security forces had surrounded Dalea city from all sides at dawn on Saturday and raided a number of houses, sparking clashes with armed groups.
The violence spread to many parts of the city, southern news website Sahwa Net reported.
Residents in Dalea told Reuters loudspeaker warnings had been issued around the city of a curfew that would begin at 6 p.m. (10 a.m. EST) and last until further notice.
North and South Yemen formally united in 1990 but many in the south, where most of impoverished Yemen's oil facilities are located, complain northerners have used unification to seize resources and discriminate against them.
Yemen became a major Western security concern after the Yemen-based regional arm of al Qaeda claimed responsibility for a failed attempt to bomb a U.S.-bound plane in December.
Western allies and neighboring oil exporter Saudi Arabia fear al Qaeda is exploiting Yemen's instability to recruit and train militants for attacks in the region and beyond.
In addition to fighting al Qaeda, impoverished Yemen is also trying to bring an end to a northern Shi'ite insurgency. Last month, the government declared a truce in the long-running conflict that drew in Saudi Arabia when the rebels seized some Saudi territory in November last year.
The kingdom launched a major military offensive against the rebels, and declared victory earlier this year, but Riyadh said at the time that the release of all captured Saudi soldiers would help prove the insurgents were serious about ending the conflict.
On Saturday, Saudi Assistant Defense Minister Prince Khaled bin Sultan was quoted by the Saudi state news agency as saying the bodies of the last two missing soldiers had been received.
Yemeni Shi'ite rebels said last month the last two missing Saudi soldiers they were believed to be holding captive were dead.
(Reporting by Mohamed Mukhashaf in Aden and Mohammed Ghobari in Sanaa; Ulf Laessing in Riyadh, Writing by Raissa Kasolowsky; editing by Noah Barkin)