The 10-year mission will involve a probe sent to a near-Earth asteroid to collect samples, said Liu Jizhong, head of China's Exploration and Space Engineering Centre.

After the sample collection from the 2016 HO3 asteroid, the probe will return to Earth orbit where it will split into two.

A capsule carrying the samples will return to Earth's surface, while a separate module will approach and orbit the comet 133P.

No timeline has been set for the mission.

A similar call was made for the lunar probe Chang'e-6, whose launch date will depend on the success of its predecessor, Chang'e-5, which will launch by the end of this year.

France's National Centre for Space Studies said last month that Chang'e-6 would carry French experiments.

Originally scheduled to collect moon samples in the second half of 2017, it was delayed after its planned carrier, the powerful Long March 5 Y2 rocket, failed during a separate launch in July 2017.

Two more moon missions have been planned, the Chinese space agency announced this year, with the ultimate goal of building a joint lunar research base.

China has ambitions of achieving space superpower status and took a major step towards that goal when it became the first nation to land a probe on the far side of the moon on January 3.

At Thursday's event, data collected from Chang'e-4 was handed to representatives from the Netherlands, Sweden and Germany, who had installed instruments on the craft.

China now spends more on its civil and military space programmes than do Russia and Japan, and is second only to the United States. Although opaque, its 2017 budget was estimated at $8.4 billion by the Organization for Economic Cooperation and Development.