Three convicted mob leaders and four convicted criminal gang members were executed Thursday in north China after their death sentences were approved by the Supreme People's Court.

The seven culprits were executed through lethal injection, conducted by the Shijiazhuang Municipal Intermediate People's Court, in the capital of Hebei Province.

The executed were all males, namely Zhang Baoyi, 47, Gao Yuehui, 49, He Pidong, 39, Liu Luntao, Zhang Guo, Li Qing and Zhang Zhiyu.

The seven were sentenced to death on charges of organizing and leading criminal gang, murder, intentionally injuring people, causing disturbance, extortion, illegally possessing and trading firearms, defamation and theft.

The Supreme People's Court approved the death sentences on the seven, who were among the 10 sentenced to death, and suspended the death penalties of the other three for two years, said Ge Qinglong with Hebei Provincial Higher People's Court.

The death penalties were handed down by the Shijiazhuang Municipal Intermediate People's Court in June 2007, and upheld by the provincial higher people's court in Hebei Province on Sept. 18, 2009.

The higher court upheld suspended death penalties for four gang members and the imprisonment of 84 others.

The trial of the 98 defendants, including 54 alleged criminal gang members, was the biggest of its kind in the province for six decades, Ge said.

Gang leaders Zhang Baoyi, Gao Yuehui, He Pidong and their accomplices were convicted of 19 crimes, including organizing a criminal gang, murder, intentionally injuring others, robbery and extortion, Ge said.

They were also charged of illegally possessing and trading firearms, fighting in public and causing disturbance.

The court found that the gang had forcibly monopolized the road haulage business in Shijiazhuang and nearby cities, and forcibly fixed prices since 2003.

The gang was involved in 38 cases of organized crimes, in which 10 people were murdered and more than 20 others injured, the court said.

The gang was strictly hierarchical and had clear divisions: operations and management; bodyguards, and hatchet men, Ge said.

Zhang Baoyi and He Pidong paid "salaries" to gang members, provided funds for criminal activities and took gang members under their wing, the court said.

China launched a nationwide campaign to crack down on gang crimes in February 2006.

Police have investigated over 1,200 gang crime cases and arrested more than 8,900 people from February 2006 to September 2009.