WASHINGTON: China has planned to construct about 1.3 million kilometres of roads and 26,000 kilometres of expressways by 2020 to bolster its military's ability to mobilise more expediently across greater spans of the country, the Pentagon has told the US Congress.

The Chinese rail network has about 100,000 kilometres of track, 10,000 kilometres of which is high-speed track supporting trains running at up to 250 kilometres per hour, the Pentagon said in its 2019 'China Military Power' report.

Beijing is initiating infrastructure projects and targeted funding allocations, it said.

"Future transportation network improvements will bolster the People's Liberation Army (PLA's) ability to mobilise by moving higher numbers of units more expediently across greater spans of the country," it said.

The PLA is the world's largest standing army.

"China expects to build about 1.3 million kilometres of roads and 26,000 kilometres of expressways by 2020," the Pentagon said in its report to Congress.

China is also improving its existing domestic airfields to handle heavier payloads, constructing airfields on islands and outposts in the resource-rich South China Sea, and restructuring airfields to support military and civilian use, it said, adding as of June 2016, about one-third of China's airports supported military and civilian use.

The PLA exercises control of China's airspace, filling a role similar to that which the Federal Aviation Administration plays in controlling airspace in the United States, it said.

Although the Civil Aviation Administration of China administers Chinese civil aviation, the PLA authority takes precedence over the airspace, the Pentagon said.

Consequently, the PLA regularly adjusts civil aviation schedules and flight paths to avoid PLA activities, such as exercises and other operations, it said.

In mid-2016, China allocated USD 600 billion as part of a three-year plan (2016-2018) to continue improving its transportation network and passed the Defence Transportation Law (DTL) authorising the management, development and production of dual-use facilities and equipment to support national and regional PLA operations, the report said.

According to the Pentagon, transportation is also at the heart of President Xi Jinping's ambitious Belt and Road Initiative (BRI), which consists of establishing roads, railways and ports to connect to countries from Asia to Africa and Europe.

"Although the BRI is marketed as primarily an effort to increase trade and development, China's improved domestic transportation infrastructure and access to transportation infrastructure abroad also would benefit the PLA by enhancing PLA access to transportation hubs and road systems," the report added.