Police have increased high visibility patrols around roads and transport stations in Scotland as a "sensible precaution" after the London bombings.
Princes Street was cordoned off to carry out controlled explosions
The Scottish Police Information and Co-ordination Centre (SPICC) said there was no intelligence to suggest any specific threat to Scotland.
However SPICC, which is speaking for all Scottish forces, warned the public to remain vigilant.
Four bombs in London killed at least 50 people and injured 700 on Thursday.
Ian Latimer, chief constable of Northern Constabulary and vice-president of the Association of Chief Police Officers of Scotland (Acpos) said: "We understand that many people will have been affected by the events in London. We have all watched with horror the events unfold.
"I would like to reassure our communities that there is currently no intelligence to suggest that there is any specific threat to Scotland but we have increased high visibility patrols around important transport facilities and stations as a sensible precaution to ensure the safety of the public.
"As ever we would urge all members of the public to remain vigilant and report anything suspicious by calling 999 or contacting the Anti-Terrorism Hotline number in confidence on 0800 789 321."
Other forces echoed the message. Grampian Police said armed officers had been deployed at "key points" across the force's area.
This was to reassure the public and Aberdeen's energy industry during the G8's climate change discussions.
The security status at the Scottish Parliament has been raised to amber.
This means that anyone entering the building, including staff passholders, will be searched and their bags put through a scanner.
Lothian and Borders Police said that the external cordon around the Holyrood building would remain in place until the completion of business relating to the G8 summit but they hoped to return to a normal security situation as soon as possible.
A Scottish Parliament spokesperson said: "On the basis of current events, the police have decided to increase vigilance throughout the city and the appropriate measures are being put into place at the parliament.
"We continue to take security advice from Lothian and Borders Police and are currently on amber alert."
Princes Street was sealed off to carry out controlled explosions
Most coach, air and rail services from Scotland to London were back to normal on Friday morning, although GNER trains were terminating at Peterborough.
Flags are flying at half-mast and the 2,500 athletes taking part in the summer Special Olympics in Glasgow observed a minute's silence for the victims of the bombings.
Bomb disposal experts were called to Alexander Removals in Bellfield Street, Dundee, after a quantity of dismantled firearms and several bags of ammonia nitrate fertiliser were found in storage boxes.
The boxes are understood to have been in storage at the unit for about 10 years.
On Friday night a bomb disposal team was called out to George Street, Edinburgh, after a suspicious package was found at Starbucks.
Lothian and Borders Police closed the road and evacuated surrounding properties but a spokesman later confirmed it was a false alarm and the road was re-opened.
The incident followed two scares in Edinburgh on Thursday when bomb disposal experts carried out controlled explosions after suspect packages were found on board a bus and outside a shop.
Police were called to Princes Street at about 1730 BST. An area between the Mound and Charlotte Square was cordoned off and all surrounding properties were evacuated.
Two controlled explosions were carried out on the bus and one on the package found on the street. Neither contained explosives. The area has been reopened.
A police spokesman said they treated the incidents seriously in light of the events in London.
An area of about 100m had been cleared around the bus, including part of Princes Street and Princes Street Gardens.