Beijing: Chinese President Xi Jinping has asked the country's submarine force to strive to become an elite force with overall competency by continuously improving its ability to fulfil missions and tasks. The submarine force, which operates in the deep sea, is tasked with glorious missions and bears great responsibility, he said in a letter to the submarine crew, state-run Xinhua news agency reported on Thursday.

He urged them to continuously improve their ability to fulfil missions and tasks, and strive to become an elite force with overall competency.

Xi called on them to make greater contributions to achieve the goals set for the centenary of the People's Liberation Army in 2027.

After he took over power in 2012, Xi, who heads the Central Military Commission, (CMC) - the high command of the PLA - has laid emphasis on developing the Chinese navy in order to increase China's global military presence.

Besides launching a large number of naval ships including three aircraft carriers, the People's Liberation Army Navy (PLAN) possesses both a nuclear-powered submarine fleet and diesel-electric submarines.

While the PLAN is currently developing its nuclear-powered submarine capabilities, its diesel-electric submarine fleet remains the backbone of China's submarine forces, according to the US based Nuclear Threat Initiative (NTI).

It quoted a US government report indicating that the submarine fleet could grow to between 65 and 70 submarines by the 2020s.