The just-concluded Fourth Plenary Session of the 19th Communist Party of China Central Committee is a political declaration of the country's determination to unswervingly uphold socialism with Chinese characteristics and firmly promote reform and opening-up in the new era, a senior CPC official said on Friday.

Wang Xiaohui, executive deputy head of the Publicity Department of the CPC Central Committee, made the remark at a news conference in Beijing.

The most important outcome of the session is that it adopted a milestone document about the CPC Central Committee's decision on major issues concerning how to uphold and improve the system of socialism with Chinese characteristics and advance the modernization of China's system and capacity for governance, Wang said.

He described the meeting as "strategically significant" as it took place at a "critical moment" for China as it strives to secure a decisive victory of completing the building of a moderately prosperous society in all respects by 2020. At the same time, on the international stage, it faces a more complicated external environment as the world undergoes profound changes.

"Adhering to and improving the system of socialism with Chinese characteristics and modernizing the country's governance system and capacity are vital to advancing the causes of the Party and the country, to the long-term stability of the nation and to the well-being of the people," Wang told reporters.

Observers said the Party used the meeting to lay the foundation for the country's future development by unveiling concrete measures to improve the country's system and capacity for governance.

A communique released after the CPC session said China's State and governance systems have notable strengths as these systems are able to push for the continuous progress of the country's nearly 1.4 billion people and ensure the rejuvenation of the Chinese nation.

Jiang Jinquan, deputy head of the Policy Research Office of the CPC Central Committee, said at the news conference that the session underlined the importance of improving the system of the CPC's leadership over all work.

Strengthening the Party's overall leadership aims to coordinate the efforts of all involved, mobilize all positive factors and increase synergies in order to efficiently advance the causes of the CPC and the country, Jiang said.

While stressing that governance for and by the people is the ultimate objective of the Party's leadership, the CPC session also called for strengthening the Party's governance capacity so as to exercise governance in a scientific and democratic way and in accordance with the law, he added.

Han Wenxiu, deputy director of the Office of the Central Committee Commission for Financial and Economic Affairs, said that the session proposed to push for new institutional arrangements for a higher-level open economy to expand opening-up in more fields.