Chinese President Xi Jinping has asked China's air force to speed up its transformation to emerge as a strong power by integrating its air and space capability on the same lines as the US.

During an inspection visit to the People's Liberation Army Air Force headquarters here, Xi who is also the chief of China's 2.3 million-strong military said the air force plays a decisive role in national security as well as military strategy and called for a balanced strength in defensive and offensive operations, PLA Daily reported.

China demonstrated its military space power when it shot down its own satellite with a ground based missile in 2007.

Recent reports said China has tested a new anti-satellite ballistic missile.

Observes say that China's confidence was boosted by several space missions using advanced cryogenic engines.

The air force must make sure it can "swiftly and effectively" deal with possible emergencies, Xi said.

He also asked it to optimise its structure and allocate more resources in a "new-type combat force".

Wang Ya'nan, deputy editor-in-chief of Aerospace Knowledge magazine in Beijing, said Xi's call for integrated air and space capability is to answer the need of the times.

"The United States has paid considerable attention and resources to the integration of capabilities in both air and space, and other powers have also moved progressively toward space militarisation," Wang said.

"Though China has stated that it sticks to the peaceful use of space, we must make sure that we have the ability to cope with others' operations in space," state run China Daily quoted him as saying.

The US air force declared in 2000 that air and space form a single "seamless operational medium" for the exercise of military power, and it would refocus its training and operating concepts to reflect that view, he said.

The idea of combining air and space capability is not new to the Chinese air force as a host of experts have underscored the importance of space.

Senior Colonel Wu Guohui, an associate professor at the PLA National Defence University, told People's Daily that the PLA air force had unfolded a series of research projects aimed at keeping pace with the latest space technologies.

He said space-based information can reshape air combat and space vehicles would be the key to forming an air-and-space weaponry system.

The construction of a modern air-defence and anti-missile apparatus could be achieved through the integration of air and space capabilities, Wu said.

Dong Wenxian, a retired researcher with the PLA air force headquarters, was quoted by PLA Daily as saying that NATO countries had actively adopted various space platforms to support reconnaissance, early warning, communication and positioning in every conflict since the first Gulf War, which indicates such platforms play a vital role in modern warfare.

He said China began to realise the significance of integrated air and space capability in the early 1990s and started courses on this issue in air force academies.