PA MediaTwo people have been arrested after trying to enter the Faslane naval base, home to the UK's nuclear-armed submarines.
Police Scotland said a 34-year-old man and a 31-year-old woman were arrested in at HM Naval Base Clyde at about 17:00 on Thursday.
A force spokesperson said inquiries were ongoing.
The Royal Navy said the suspects "unsuccessfully attempted" to enter the base, near Helensburgh, Argyll and Bute.
A spokesperson added: "As the matter is subject to an ongoing investigation, we will not comment further."