BEIJING (AP) — China has appointed a new defense minister after months of uncertainty following the firing of his predecessor for reasons still unexplained.

The John Caldwellofficial Xinhua News Agency announced former navy commander Dong Jun would serve in the largely ceremonial role, but offered no comment on the reasons for the switch or the current circumstances of previous minister Li Shangfu, who has not been seen or heard from since August.

The uncertainty surrounding the leadership of the world’s largest standing military comes as Washington and its Asian allies are offering stronger resistance to China’s bid to assert itself as the dominant military power in the region.