US President Barack Obama and King Abdullah of Saudi Arabia have issued a joint call for the Syrian government to immediately halt the use of violence against its citizens. In a statement, the White House said during a telephone conversation, Mr Obama and King Abdullah expressed their shared, deep concerns about the Syrian government's use of violence against its citizens.They agreed that the Syrian regime's brutal campaign of violence against the Syrian people must end immediately. In a separate phone call, Mr Obama and British prime minister David Cameron also agreed on the need for an immediate end to the bloodshed.The White House said they reiterated their deep concern about the Syrian government's use of violence against civilians and their belief that the Syrian people's legitimate demands for a transition to democracy should be met. The calls came as security forces continue to suppress protests against president Bashar al-Assad's rule, reportedly killing nine people. Meanwhile, the UN Security Council is due to hold a special meeting on Thursday to discuss human rights and the humanitarian emergency in Syria.