BEIJING (Reuters) - China's anti-corruption watchdog said on Saturday that it had uncovered evidence of graft at China Petrochemical Corp (Sinopec Group), warning the state-owned oil giant to take strong action to eradicate kickbacks, nepotism and theft.

Sinopec, the parent company of China Petroleum & Chemical Corp , must take steps to stop "power-for-money dealings" and prevent the loss of state assets, the Central Commission for Discipline Inspection (CCDI) said.

Some executives are suspected of corruption in areas of project construction, supply, sales, joint-ventures, and overseas operations, the agency said in a statement on its website (http://www.ccdi.gov.cn/).

It also said businesses set up by families and relatives of managers have profited from their connections.

The statement quoted Sinopec Chairman Fu Chengyu pledging to "take real and tough actions and severely punish corruption".

China has stepped up inspections, focusing on strategic firms, as it prepares to carry out its most ambitious reform of state-run industrial conglomerates in nearly two decades.

President Xi Jinping has warned that corruption is a threat to the Communist Party's survival and has vowed to go after powerful "tigers" as well as lowly "flies".