A Chinese submersible embarked on what the crew hoped would be the country's deepest manned dive ever Tuesday, state media reported, as it seeks to exploit the vast resources of the ocean floor.
The Jiaolong undersea craft -- named after a mythical sea dragon -- set off on the test dive in the northeastern Pacific in the early hours, the official Xinhua news said, citing the State Oceanic Administration.
Chinese technical capabilities have gathered pace in recent decades, exemplified by a fast-growing space programme that in 2003 made China just the third nation to conduct manned space flight.
The craft is designed to reach a maximum depth of 7,000 metres and it carried three people to 4,027 metres below sea level in a test on Thursday.
But its attempt to reach 5,000 metres the following day was postponed due to unfavourable sea conditions.
The Jiaolong's range theoretically gives China access to nearly all of the world's deep-sea areas, and Xinhua quoted the submersible's chief designer Xu Qinan as saying its "state-of-art" digital underwater communication systems and undersea mobility systems allowed it to "move back and forth easily under the sea".
Although much of the craft's components were produced in China, some had to be imported from abroad such as the underwater high-definition video-shooting and transmission equipment, Xu told Xinhua.
The deepest dive ever conducted was by the US Navy, which reached the bottom of the Mariana Trench -- the deepest point in the world's oceans at 11,000 metres -- in 1960 in a manned undersea craft.
China has said its development of submersible technology is aimed at scientific research and the peaceful exploration and use of natural resources.
The country has pushed hard in recent years to obtain oil, minerals and other natural resources needed to fuel its growth.
Explore further: Strong quake hits east Indonesia; no tsunami threat