China's manned submersible Jiaolong and its three divers rose from over 6,000 meters below the sea in the Mariana Trench after setting the country's deep-sea diving record on Friday.

The dive, which began at 9 am Friday, was the first of a series of six scheduled ones.

The dive went smoothly, with Jiaolong taking three hours to reach the depth of 6,671 meters at noon local time. The mark surpassed the 5,188-meter record Jiaolong made last July.

The vessel's three divers - Ye Cong, Cui Weicheng and Yang Bo - passed on their wishes for the successful launch of China's Shenzhou-9 spacecraft scheduled on Saturday, while 6,055 meters below the sea.

Jiaolong threw ballast iron and began to rise at 12:44 pm local time. The three divers and the vessel were all reported to be in good condition.

Earlier, something had been reported going wrong with the submersible's No.1 communication system. However, the No.2 system worked soundly to guarantee communications between the vessel and Xiangyanghong 09, its mother ship.

The submersible rose to the surface at about 2:30 pm local time.

Jiaolong, depending on local weather and sea conditions, will attempt to make another five deeper dives in the coming days. The fifth and sixth dives aim to reach a depth of 7,000 meters.

The six dives, each of which lasts between eight and 12 hours, will test various functions and performances of the manned submersible at great depths.

To ensure the crew's safety, sea dives can only be made in daylight under less than four-class winds and less than three-class waves.

The Xiangyanghong 09 ship reached the designated dive zone in Mariana Trench - home to the world's deepest waters in the western Pacific Ocean - on Monday morning.

Jiaolong has enabled China to join the ranks of other countries including the US, Japan, France and Russia, which all have manned deep-sea submersible vessels. Jiaolong is capable of diving in around 99.8 percent of the world's oceans.