Three packages containing “white powder type substances” have been sent to political offices this week, the Scottish Parliament said today in a statement.
The parcels, described as "suspicious", were sent to an elected official, a political party headquarters and a local council building between 25 April and 26 April.
Police inquiries are underway and further advice has been issued to elected representatives across Scotland, Holyrood officials said.
The white powder is believed to have arrived along with material relating to the forthcoming general election, the Daily Mail reports.
Earlier on Thursday police said a man carrying knives had been arrested not far from Downing Street, just weeks after a terror attack in Westminster left five people dead.
Khalid Masood ploughed a car into pedestrians on Westminster Bridge on 22 March, before stabbing to death a police officer in the grounds of parliament.
Earlier this week, Labour peer Peter Hain revealed police are investigating a letter sent to him containing white powder.
Police on Tuesday said they were investigating a suspicious package sent to the East Dunbartonshire office of SNP MP John Nicolson.
Additional reporting by Reuters