Two men arrested in Scotland in connection with the Glasgow Airport attack are not "home-grown terrorists", Justice Secretary Kenny MacAskill said.
His comments followed searches of a number of homes in Neuk Crescent, Houston, Renfrewshire.
Mr MacAskill said the suspects were not "born or bred" here but had lived in Scotland for a "period of time".
"For any suggestion to be made that they are home-grown terrorists is just not true," he added.
Resident Stewart McArthur said the police arrived in Neuk Crescent just before 0500 BST.
"They were in an unmarked transit van and they were wearing balaclavas," he said.
"It was like an American Swat unit here. And they were really heavily armed."
The airport is starting to return to normal although many flights are still cancelled or delayed.
The reopening will be "extremely gradual", the airport official added.
Strathclyde Police have linked the attack to the discovery of two car bombs in London's West End on Friday.
As a result of both incidents, the UK has moved to its highest level of terror alert - critical.
A further two people have been arrested in Cheshire and another in Liverpool.
Scottish ministers met earlier for a briefing on developments.
The summit was led by First Minister Alex Salmond and attended by Mr MacAskill, Scotland's top law officer, Lord Advocate Elish Angiolini and the country's most senior civil servant, Scottish Executive permanent secretary Sir John Elvidge.
Scotland's equivalent of Westminster's Cobra emergency committee is the Scottish Executive Emergency Room (Seer).
Mr Salmond, who has appealed for public vigilance, has said no community should be scapegoated as a result of the Glasgow incident.
Muslim leaders held an emergency meeting in Glasgow to discuss fallout from the attack.
Scotland's only Muslim MP Mohammed Sarwar said threats had been made towards members of the Muslim community in the aftermath of the attack in Glasgow.
He told BBC Scotland he had taken calls from people who had been threatened or targeted by abusive graffiti.
Mr Sarwar said people in the Muslim and Asian communities were "very angry".
"They're concerned about a backlash and that's why the emergency meeting has been called," he said.
Osama Saeed, from the Muslim Association of Great Britain, said: "I think, personally, it's so close to home that it's a completely different emotional reaction."
The accident and emergency department at the Royal Alexandra Hospital, Paisley, where one of the suspects is being treated for burns, is now open and fully functional.
Police surround the house in Houston (Picture from BBC viewer)
The suspect remains in a critical condition.
A member of the public is being treated in the Southern General Hospital in Glasgow, in connection with Saturday's attack.
He has been described as being in a stable condition.
Security has been tightened at Scotland's other airports.
The access road to Edinburgh Airport has been closed and armed police are patrolling the Forth road and rail bridges.
Lothian and Borders Police said they had also increased security at other key sites across the city, including the castle and Holyrood Palace.
At the Scottish Parliament some of the entrances have been closed with visitors going through stricter security screening.
Anyone with information should contact the Strathclyde Police incident room on 0800 0560944.