A Yemeni policeman was shot dead by unidentified gunmen in the southern Yemeni city of Ad Dali on Monday. A security source told Arabstoday that gunmen opened fire on the security official's vehicle as he was heading to work in the morning. The perpetrators were able to flee from the scene. Although there has been no official comment from the government, the security source claimed that the gunmen were part of the armed wing of the South Yemen Movement, seeking an independent state of South Yemen through the use of force.      There has been an upsurge in incidents targeting security and military personnel in Ad Dali over the last few years. After the former North and South Yemen united in 1990, the south broke away in 1994, triggering a short-lived civil war that ended with the region being overrun by northern troops.