China on Friday launched an investigation into FedEx for "failing to deliver express packages" to the correct addresses in the country, state media said, after the US delivery service misrouted some Huawei parcels.
FedEx apologised earlier in June for the delivery mishap after Chinese telecoms giant Huawei said it was reviewing its ties with the package service over the incident.
The US delivery firm said at the time that "no external parties requested that FedEx transfer these packages".
"China's relevant government department has started an investigation into FedEx, delivering a notice of inquiry to FedEx China," Chinese official news agency Xinhua reported on Friday, without specifying which department.
Beijing's investigation into FedEx comes as Huawei faces moves from the US to blacklist the Chinese tech firm, cutting it off from American-made components it needs for products -- though it was issued a 90-day reprieve in May.
China hit back in May by announcing it would create its own blacklist of "unreliable" companies and individuals, which could target US and international firms that have cut off supplies to Huawei.
Last week, China's commerce ministry said the list would not target any specific field or company, but that it was "designed in reaction to practises distorting the market for non-commercial purposes."
A separate list system to "more effectively forestall and defuse national security risks" is also in the works, according to a report last week by Xinhua.
The Chinese news agency did not elaborate or state whether the move was linked to the trade war but said detailed measures would be unveiled in the "near future".
US President Donald Trump is expecting to meet with his Chinese counterpart later in June at the G20 summit in Japan, though Beijing has not confirmed whether Xi Jinping will attend.
A Trump-Xi meeting would mark a turning point in the bruising trade dispute between the world's two biggest economies, which has spooked markets worldwide and sparked worries about the global economy.
Negotiations to resolve the dispute stalled last month after Washington increased tariffs on $200 billion worth of Chinese imports, sparking retaliation from Beijing.