SHANGHAI (Reuters) - Trading in shares of Chinese oil producer PetroChina Co Ltd will resume in the afternoon after a brief suspension, the firm said on Monday. The shares were suspended after a media report said company director Wang Guoliang and vice president Sun Longde were being investigated. PetroChina said the report was inaccurate. "Wang Guoliang and Sun Longde are still working in their respective positions," PetroChina said. The China Business News reported on Monday that five executives, including Sun and Wang, had been detained, citing an unidentified source within the company. (Reporting by Fayen Wong. Editing by Dean Yates)