SANAA - A Yemeni court on Tuesday sentenced a leading member of a southern separatist movement to 10 years in prison, a move that could further heighten tensions between secessionists and the government. Violence between Yemeni security forces and southern separatists protesting against the government of President Ali Abdullah Saleh worsened this month. The judge at a court in Sanaa said in his verdict that Ahmad Bamuallim, a former parliamentarian, had been calling for an "armed insurrection" and spreading "division and hatred". North and South Yemen united in 1990, but many in the south -- home to most of Yemen's oil industry -- complain northerners have seized resources and discriminate against them. Bamuallim said in court he would not appeal the verdict. "This verdict is invalid and was issued by a court that is itself invalid, and this will not prevent me from continuing my peaceful struggle," he said. In the southern port of Aden, a court handed a 15-month jail sentence to Ali al-Saidi, a retired general, for "threatening national unity", a judicial official said. Sanaa, struggling to stabilise a fractious country, has come under international pressure to end a northern war and focus on fighting al Qaeda, whose Yemen-based arm claimed responsibility for a December attack on a U.S.-bound plane. Last week, the president declared an end to a long-running conflict with northern Shi'ite rebels that drew in neighbouring Saudi Arabia last year. Western countries and neighbouring Saudi Arabia, the world's biggest oil exporter, fear al Qaeda is exploiting instability in impoverished Yemen to launch attacks in the region and beyond.