China on Saturday signalled at increasing its defence budget, the second biggest after the US, citing "complex security challenges" ahead of its annual Parliament session during which it will unveil a new ministerial and official leadership, including a successor to Premier Li Keqiang.The annual season of China's rubber-stamp Parliament began on Saturday with the opening meeting of the top advisory body the Chinese People’s Political Consultative Conference (CPPCC) while its national legislature, the National People’s Congress (NPC), will begin its session on Sunday.