BEIJING — China has convicted nearly 150,000 people for corruption since 2008, state media said on Tuesday, citing figures from the state prosecutor which underlined the scale of graft in the country.

President Xi Jinping, who took office in March, has called corruption a threat to the ruling Communist Party's survival and vowed to go after powerful "tigers" as well as lowly "flies".

His latest crackdown has netted a handful of senior officials, among them former executives from oil giant PetroChina.

Nearly 66,000 officials have been investigated for taking bribes and another 23,246 people for giving them, prosecutor-general Cao Jianming said, according to Xinhua news agency.

Despite China's drive to rein in corruption, Cao told the country's legislature that enforcement agencies were still understaffed. "Some of our investigators rely too much on confessions rather than evidence," he said.

"There were still cases where the legal rights of parties were seriously violated during graft investigations. A few investigators abused their power," he added.

About 4,800 cases involved bribes of at least 1 million yuan ($164,000) or embezzlement of at least 10 million yuan.

More than 13,000 of the nearly 200,000 people investigated between January 2008 and August of this year were officials at county administration level or above, including 32 at ministries.

The most high profile recent case was the conviction of Bo Xilai, once a rising star in China's leadership, who was jailed for life in September after a murder scandal involving his wife, Gu Kailai, which shook the party.

A court is set to rule on his appeal against the corruption, bribery and abuse of power conviction on Friday.