The Chinese Communist Party will start a key meeting to prepare for its National Congress, which is held every 5 years.
Attention is focused on how President Xi Jinping, who will start his second term, will consolidate his power and which policy he will prioritize.
The Central Committee will open a general meeting on Wednesday in Beijing to discuss agendas in advance.
The congress is due to start on October 18th, with about 2,300 delegates taking part.
Xi will present basic political and economic policies for the next 5 years. The delegates will discuss a draft revision of the party's constitution that is expected to incorporate Xi's guiding principles.
Some people expect that the principles will be written into the document under his name to place him as an equal to former leaders Mao Zedong and Deng Xiaoping.
The Central Committee will convene a general meeting again on the day after the congress closes to elect new members of the Politburo Standing Committee.
A large number of police officers and vehicles are deployed in Beijing to ensure security ahead of the congress.
Chinese media report that more than 850,000 citizens have signed up as security volunteers. They are seen patrolling in various locations in the capital.
The capital is decorated with red banners carrying a slogan that calls for unity under the party with Xi as its core.