China's manned deep-sea submersible Jiaolong prepares to be put into water to make a fourth dive into the sea at the Mariana Trench on June 24, 2012. China's manned submersible, Jiaolong, made its fourth dive in the Mariana Trench on Sunday morning to attempt the world's first 7,000-meter dive below the surface of the Pacific Ocean. [Xinhua]?

Chinese oceanauts refreshed the country's dive record in a manned submersible by going deeper than 7,000 meters beneath the sea after a successful test dive in the Pacific Ocean Sunday morning.

The Jiaolong, China's manned submersible named after a mythical sea dragon, succeeded in diving 7,020 meters below sea level during its fourth dive into the Mariana Trench.

The dive started at 7 a.m. local time Sunday in heavy rain.

The three oceanauts, namely Ye Cong, Liu Kaizhou and Yang Bo, sent greetings from the bottom of the blue sea to the three astronauts who are expected to conduct a manual docking of the Shenzhou-9 spacecraft with the orbiting Tiangong-1 lab module.

"We wish for a great success of the manual docking and brilliant achievements in China's manned space and manned deep-sea dive causes," said the oceanauts.

The oceanauts had succeeded in reaching the depths of 6,671, 6,965 and 6,963 meters in their previous three dives from June 15 to 22, well surpassing the record of 5,188 meters last July.

"It has been proved during the four times of dive that the submersible is stable in function and the capabilities of the team performing the test dives are rising gradually," said on-scene commander Liu Feng.