Local police commander Chief Inspector Paul McCracken said: “Police enquiries are ongoing but as our priority is keeping people safe, we would ask that anyone who knows anything about this incident to get in touch with us.

“I would ask everyone to be vigilant.

“If anyone finds anything suspicious, under no circumstances should they touch it, they should phone police immediately.

“Please call police on the non-emergency number 101, quoting reference 68 of 14/6/17.

“Alternatively, if someone would prefer to provide information without giving their details they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.”