Anti-terrorism police and bomb disposal units have been called to a wooded area in West Dunbartonshire which is thought to have been damaged in an explosion.
Strathclyde Police were called to reports of an explosion in Garadhban Forest, near Gartocharn, at about 1200 GMT on Wednesday.
The area, to the south east of Loch Lomond, has been sealed off.
Police said enquiries were ongoing to establish the full circumstances surrounding the incident.
Ch Sup Calum Murray, of Strathclyde Police, said: “As you would expect, when we are dealing with a situation where we suspect that explosives may be involved, it is our immediate priority to assess the situation and to call on expertise where we think it is appropriate.
“By its very nature, this type of assessment and investigation is complex and does take time. I can confirm that we are currently being assisted by agencies from across the UK.
“I would stress that the site is secure and that there is no risk to public safety.”
This article is from the BBC News website. © British Broadcasting Corporation, The BBC is not responsible for the content of external internet sites.