He said that Baoum arrived in the port city from nearby Lahij earlier in the day with the intention of joining the protest.Police have killed 10 people in Aden in the past week, according to an AFP tally, as they resorted to gunfire to disperse frequent protests against the government of President Ali Abdullah Saleh.

Baoum had only come out of custody earlier this year after a previous arrest on November 9.Baoum heads the supreme council of the Southern Movement, the main organiser of protests in the south in recent months. The movement's members want either secession or increased autonomy for the formerly independent region.

Residents complain of discrimination by the Sanaa government in the distribution of resources since union between north and south in 1990.The south broke away again in 1994, sparking a brief civil war that ended with the region overrun by northern troops.