China's supreme court and procuratorate vowed Thursday to step up anti-corruption efforts after a string of high ranking officials fell in last year's clean-up campaign.

Prosecutors will focus on work-related crimes, commercial bribery and crimes that seriously infringe on people's interests this year, Prosecutor-General Cao Jianming told lawmakers in his work report to the parliament.

More attention will also be given to criminal cases behind mass incidents and accidents, cases concerning construction projects, real estate development, land management and mineral resource exploration, Cao told nearly 3,000 lawmakers at the annual session of the National People's Congress (NPC).

These areas are where corruption usually hide.

Officials acting as "protective umbrella" for gangs will also be a focus of prosecutors' agenda this year, Cao said.

In the work report of the Supreme People's Procuratorate (SPP), Cao said the country's prosecutors launched graft probes against 2,670 officials above county level last year, including eight at the provincial or ministerial level.

The eight high-ranking officials included Huang Songyou, former vice president of the Supreme People's Court and Wang Yi, former vice president of the state-run China Development Bank.

Also on the list were Chen Shaoji, former top political advisor of southern Guangdong Province, and Wang Huayuan, a former provincial official in eastern Zhejiang Province.

Altogether, prosecutors investigated about 41,000 people, down 3.3 percent, in more than 32,000 cases, up 0.9 percent, for embezzlement, bribery, dereliction of duty and other work-related crimes last year, according to Cao's report.

Among the probed, more than 18,000 were "extremely serious" corruption cases, while 3,100 were grave cases in connection to dereliction of duty or infringement of people's rights, it said.

More than 9,300 government workers were implicated in cases of dereliction of duty, malfeasance and infringement of people's rights, Cao said.

Nearly 3,200 bribers were punished "in an effort to strengthen crackdown on bribery offering crimes," he said.

Cao said the authorities seized more than 1,100 on-the-run suspects involved in work-related crimes, with more than 7.1 billion yuan (about one billion U.S. dollars) embezzled or received in bribes recovered.

NPC deputy Zhu Yong, also a political and law official in the provincial Communist Party committee in the eastern Anhui Province, said strict anti-corruption measures, such as auditing on officials who are leaving their posts, have produced fruitful results in fighting corruption.

However, Zhu said some officials are still vulnerable to the temptation of bribes, and so fighting graft remains a challenge.

Fighting graft is a very difficult task worldwide and cannot be efficiently addressed in a short period of time, Zhu added.