Following the departure of some Russian Navy ships from the Mediterranean, today was the turn of a Chinese navy unit, a Type 636 hydrographic survey ship that passed Gibraltar heading west this afternoon.
Officially the ship is a scientific research unit but, as well as similar Russian units, the doubt that alongside the scientific use is an espionage use (given its equipment it is also one that can keep an eye on submarine cables and pipelines) is very strong.
We do not know when the unit entered the Mediterranean (via Suez) nor was it possible to track it accurately during its Mediterranean cruise.