(Corrects to say officials taken away, not detained)
HONG KONG/BEIJING Dec 17 (Reuters) - The Chinese government has questioned two more senior executives of China National Petroleum Company (CNPC) as part of a wider graft investigation into the state energy giant, two people with direct knowledge of the matter told Reuters.
CNPC and its listed unit PetroChina are at the centre of one of the biggest corruption investigations into the Chinese state sector in years.
Wen Qingshan, CNPC's chief accountant, and Wang Lihua, head of PetroChina's oil trading vehicle Chinaoil, were taken away by authorities last week, said the people, who cannot be named as they are not authorised to talk to the media. Wang is also CNPC's deputy chief economist.
It was not immediately clear whether the two officials were themselves the target of the investigation or were assisting in the broader probe of the state oil giant.
Beijing stunned the Chinese energy industry in August-September with announcements that five former top executives at PetroChina and CNPC were being investigated for "serious discipline violations" - shorthand generally used to describe graft.
They included Jiang Jiemin, former chairman of both entities, and Wang Yongchun, who was vice president of CNPC in charge of China's largest oilfield at Daqing in the country's northeast.
Authorities have given no further details on what these officials may have done wrong, but the investigations suggest China's President Xi Jinping wants to tackle graft in an industry that ranks as one of the most powerful corners of the state-owned corporate sector.
Wen, 54, was also appointed chairman of listed Kunlun Energy in August, replacing Li Hualin, who the company said was being investigated by authorities. Kunlun Energy shares were suspended early on Tuesday.
Wang, one of the few top female executives of the state giant, has since 1998 been chief of Chinaoil, one of the largest Chinese oil traders, which has over the years expanded rapidly into an influential player in the global oil market.
Neither PetroChina nor CNPC could be reached immediately for comment. It was not possible to contact Wen or Wang. (Reporting by Chen Aizhu and Charlie Zhu; Editing by Dean Yates)