The Chinese government announced a cabinet reshuffle involving the replacement of Qin Gang as the Minister of Foreign Affairs during the fourth session of the 14th National People’s Congress Standing Committee on Tuesday.

Qin Gang, China’s youngest-ever foreign minister at 55, has not been seen in public since June 25. He last attended official meetings in Beijing, where he met with US Secretary of State Antony Blinken. However, he has since missed several high-level diplomatic events that he was expected to attend, including the visits to China of US Treasury Secretary Janet Yellen, US Special Presidential Envoy for Climate John Kerry, and former US Secretary of State Henry Kissinger.

Chinese officials have not commented on Qin’s whereabouts or the reason for his absence. Government official websites and state media have also removed information about and speeches by Qin, who has been replaced with Politburo member and veteran diplomat Wang Yi for upcoming conferences. James Mayger, Bloomberg’s Beijing correspondent, tweeted earlier this month about his exchange with Chinese Ministry of Foreign Affairs Spokesman Wang Wenbin regarding the health explanation for Qin Gang’s absence. Wang told Mayger that a statement had already been made, but the Q&A regarding Qin’s health was missing from the press conference record.

The sudden replacement of China’s foreign minister has also raised international and domestic concerns about the country’s foreign policy, particularly its relations with the US. Qin’s previous experience as China’s ambassador to the US made him a valuable asset in maintaining communication between the two countries.

The “disappearance” of top officials is not uncommon in China’s opaque political system. However, the lack of any official reason or explanation for the latest removal has sparked conjecture and questions about transparency within China’s leadership. Until Chinese authorities provide clarification about Qin’s status, health or reasons for his replacement, uncertainty and speculation will likely continue to swirl around one of China’s highest-profile diplomatic roles during a sensitive time in China-US relations.