A 33 year old man remains critical in hospital.
Sturgeon: We Feel Solidarity With London
Nicola Sturgeon has said Scotland feels a sense of solidarity with the people of London in the wake of the terrorist attack at Westminster.
The First Minister spoke after the events in the UK capital led to the suspension of a major Holyrood debate and saw security stepped up at locations around Scotland.
Five people, including an unarmed police officer, have died and dozens were injured in the incident on Wednesday afternoon.
Ms Sturgeon said: "My thoughts, as I'm sure the thoughts of everybody in Scotland tonight, are with people caught up in this dreadful event.
"My condolences in particular go to those who've lost loved ones.
"My thoughts are with those who've sustained injuries and we all feel a sense of solidarity with the people of London tonight.''
She has convened a Scottish Government resilience (SGoRR) meeting to "review any implications for Scotland''.
"It is important to stress that there is no intelligence of any risk to Scotland,'' she added.
Armed patrols have been increased around key sites in the Scottish capital, while police patrols have also been upped elsewhere across Scotland.
Police Scotland Chief Constable Phil Gormley, who confirmed the moves, described them as "reassurance measures''.
Officers are also continuing to "dynamically review'' safety and security plans and operations in the wake of the incident at Westminster, and they have urged the public to stay alert.
Mr Gormley told a meeting of the Scottish Police Authority (SPA) on Wednesday: "We have increased armed patrols around key sites in Edinburgh and there will be higher-profile patrols across key locations in Scotland.
"We've uplifted and deployed a number of armed officers into key places so they are able to respond if the need suggests and we're working very closely with colleagues in London to understand what exactly has happened and what we need to do to support them and to keep Scotland safe.''
He later tweeted: "Tonight we send our condolences to the family & colleagues of the Met Police officer killed in the incident.''
Assistant Chief Constable Bernard Higgins said Police Scotland "continues to dynamically review all safety and security plans and operations''.
In a statement, he said: "An element of this includes ensuring our armed policing and specialist resources are appropriately deployed. We are monitoring the situation closely.
"I would urge the public to remain alert and report any suspicious activity to the police.
"We continue to liaise with the UK authorities in response to this incident and our thoughts are with those affected by the events in London.''
Security at the Scottish Parliament has been heightened as a precaution, with officials stressing there is no specific threat to Holyrood or Scotland.
Flags at the Scottish Parliament are flying at half-mast as a mark of respect.
Earlier, the Holyrood vote expected to back Ms Sturgeon's calls for a second Scottish independence referendum was put on hold following the terror attack.
MSPs had been due to vote on whether the Scottish Government should seek discussions with the Conservative administration at Westminster on the details of a section 30 order - the legal mechanism that would allow a second independence ballot to be held.
But the Scottish Parliament suspended business in the wake of the London incident.
The Holyrood debate and vote will now take place at another time, with party bosses meeting on Thursday morning to discuss the rescheduling issue.
Files will be handed to the Scottish Criminal Cases Review Commission.
It's predicted the Tories could win a number of seats in Scotland.
Police Scotland say the "targeted attack'' happened at the man's home in Uddingston.
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