Forty-two people have been jailed in China for smuggling more than 700 people out of the country, state media reported.

Four defendants, Chen Wenshu, Wang Cheng, Bai Yuquan and Jin Jiming, were sentenced to life in prison for leading Communist China's biggest-known smuggling ring, which operated between June 1998 and November 2000.

Another 38 people were sentenced to between two and 15 years, Xinhua news agency reported.

Most of them were shipping company officials and crew from east China's Anhui, Fujian and Zhejiang provinces, court officials said.

The Intermediate People's Court in Nanjing heard that 38 trips were made by boats illegally ferrying 713 people to Japan via South Korea.

Many of those sentenced in Nanjing bought or leased ships, built secret compartments to carry migrants and bought forged or stolen seamen's licenses, officials said.

Some were also convicted of illegal possession of ammunition.

Illegal migrants pay smugglers, known as snakeheads, tens of thousands of dollars per head to help them get abroad.

Japan raid

This particular smuggling ring was discovered in November 2000 when a group of 17 stowaways on a Chinese ship were found by Japanese coast guards.

All those smuggled in that operation came from the south eastern province of Fujian, which has a history of people smuggling despite being relatively wealthy.

Human smuggling from China hit Western headlines in June 2000 when 58 people from Fujian were found suffocated in a truck at the British port of Dover.

Two survivors from that incident told a court they had paid snakeheads $20,000 each to help them reach the West, where they hoped for a better life.