Image copyright Reuters Image caption Thousands of Chinese officials have been investigated on suspicion of graft and corruption

Anti-corruption investigators in China have confirmed the reported seizure of the equivalent of $33m in cash at an official's home in May - the biggest such haul to date.

More than 200m yuan (£20m) were found and four out of 16 counting machines broke whilst measuring the notes, a prosecutor said.

Senior energy official Wei Pengyuan is under investigation for corruption.

President Xi Jinping has promised to tackle corruption in China.

The massive haul, first reported in the Chinese press in May, was confirmed at a news conference by top anti-bribery prosecutor Xu Jinhui.

Mr Wei, who is the deputy chief of the National Energy Administration's coal department, was put under investigation in May for allegedly accepting bribes following the discovery of the hidden cash.

China has sentenced more than 13,000 officials found guilty of corruption and bribery in the first nine months of 2014 alone.

President Xi warned that his campaign against corruption would target both "tigers" and "flies", indicating that no-one, even senior party members, was exempt from the crackdown.

Since he came to power, some of China's biggest political heavyweights, including the vice-chairman of China's parliament and the former security chief have been targeted by the anti-corruption campaign.

Experts have even suggested that the proportionately high number of suicides among party officials is down to the pressure from the battle against corruption.