A protester was killed during clashes with security forces in the Cambodian capital late Sunday, witnesses said, while several other supporters of the opposition party who dispute premier Hun Sen\'s election win were injured. \"I saw with my own eyes he is dead. He was shot in the head... live ammunition must have been used,\" said Ou Virak, president of the prominent Cambodian Center for Human Rights, adding he did not know who had killed the man. Two other witnesses told AFP the man was killed during clashes, while Ou Virak said at least 10 other demonstrators were injured as police fired tear gas at rock-throwing protesters.