China on Tuesday launched the world's first quantum satellite, which will help it establish "hack-proof" communications between space and the ground, state media said, the latest advance in an ambitious space programme.

The programme is a priority as Xi Jinping, the president, has urged China to establish itself as a space power, and apart from its civilian ambitions, it has tested anti-satellite missiles.

The Quantum Experiments at Space Scale, or QUESS, satellite, was launched from the Jiuquan Satellite Launch Centre in the remote northwestern province of Gansu in the early hours of Tuesday, the official Xinhua news agency said.

"In its two-year mission, QUESS is designed to establish 'hack-proof' quantum communications by transmitting uncrackable keys from space to the ground," it said.