A security incident is 'ongoing' at the Royal Navy's warfare school, HMS Collingwood in Fareham.
It is thought that the incident could involve a suspicious package but the MoD have not confirmed this.
A spokesperson said, "We can confirm there is an ongoing incident at HMS Collingwood, the Royal Navy warfare school in Fareham, Hampshire.
"It would be inappropriate to comment further at this stage."
HMS Collingwood is the headquarters of the navy's Maritime Warfare School and Surface Stream, delivering training including weapon engineering, diving,physical training, chemical biological radiation nuclear and damage control, sea survival, seamanship and military skills.