ADEN, Yemen A Yemeni soldier was killed and two others wounded, along with two passers-by, during a clash between the army and southern separatists near Aden on Saturday, a security official said.
The clash took place in the town of al-Hawat, in al-Lahej province just north of Yemen's second city and main seaport, after separatists tried to close the marketplace.
Bringing stability to impoverished, turbulent Yemen is a priority for Washington and Gulf Arab states who fear that a further collapse of central rule will allow al Qaeda to build a launchpad for attacks with global reach.
The group's Yemen-based wing has been described by U.S.-officials as the movement's most dangerous.
Yemen's southern separatist movement is one of several big challenges for an interim government in Sanaa, formed after street protests helped oust long-time ruler Ali Abdullah Saleh last year.
The government also faces a rebellion by the Zaydi Shi'ite Houthi movement in the north of the country, an insurgency by Islamist militants east of Aden, splits in the military and a humanitarian crisis.
The Houthis and the southern secessionists are involved in a "national dialogue" aimed at reconciling the country's many different factions around a transition towards democracy.
The old Communist state of South Yemen united with the north in 1990, but the two retained parallel governments and armies until a brief civil war in 1994 won by the north.
Many southerners later complained of discrimination from Sanaa, pointing to what they see as the unfair distribution of money from oil fields located in the former South Yemen.
(Reporting By Mohammed Mukhashaf; Writing by Angus McDowall in Riyadh; Editing by Stephen Powell)