Several packages containing “suspicious” white powder have been sent to politicians’ offices across Scotland.
The targets included the SNP’s headquarters in Edinburgh.
Three packages containing a “white powder” were delivered to the office of the Nationalist MP John Nicholson in East Dunbartonshire on Tuesday.
A separate package was delivered to the Angus Council offices in Forfar on Wednesday containing a message “Get SNP out. Tories In.”
Police have issued advice about dealing with suspicious packages after the string of incidents.
A statement issued to MSPs Thursday by Scottish Parliament security chiefs said: “All packages were associated with the forthcoming UK general election.
“Police Scotland’s enquiries into this matter are ongoing.”
A letter from Police Scotland has also been distributed to MSPs with further advice regarding mail handling, suspicious packages and indicators of “white powder”.
The statement to MSPs added: “We would be grateful if you would take the time to review this information and discuss with your local office staff.
“The same information has been issued to all elected representatives across Scotland.”
The package sent to Mr Nicholson’s East Dunbartonshire constituency office was “intended to cause,” the MP said afterwards.