Nicola Sturgeon tweeted in response to the “heartbreaking” news from Manchester, calling the incident a “barbaric attack”.
The First Minister was set to chair a meeting of the Scottish Government’s resilience committee with police to be updated on the attack.
In a statement, Ms Sturgeon said: “My thoughts are with the victims, their families and all those who have been affected by this barbaric attack in Manchester.
“The Scottish Government is working with Police Scotland and the UK Government to ensure that we have a full understanding of the developing situation.
“I will convene a meeting of the Scottish Government’s Resilience Committee this morning to receive an update and to consider any implications for Scotland.”
The SNP candidate for the Western Isles, Angus MacNeil, tweeted a picture of two girls from the island of Barra in his constituency, Laura MacIntyre and Eilidh Macleod, who he said were in Manchester and were missing.
Candidates from all parties posted on social media that they were cancelling local events in their constituencies.
Theresa May was also set to convene a meeting of the emergency COBRA committee in London on Tuesday morning.
The Prime Minister said: “We are working to establish the full details of what is being treated by the police as an appalling terrorist attack.
“All our thoughts are with the victims and the families of those who have been affected.”
Party leaders cancelled campaign stops and expressed their condolences with the families of those killed and injured.
Labour leader Jeremy Corbyn said: “I am horrified by the horrendous events in Manchester last night. My thoughts are with families and friends of those who have died and been injured.
“Today the whole country will grieve for the people who have lost their lives.
“I have spoken with Andy Burnham, the mayor of Manchester, who has fully briefed me on the operational response in the city.
“I would like to pay tribute to the emergency services for their bravery and professionalism in dealing with last night’s appalling events.
“I have spoken with the Prime Minister and we have agreed that all national campaigning in the general election will be suspended until further notice.”
The Scottish Labour leader Kezia Dugdale said it was “a barbaric and sickening attack, targeted at young and vulnerable people enjoying a night at a concert” and a “heartbreaking moment for our country”.
Ms Dugdale said: “Across the UK we are today grieving for the people of Manchester. I pay tribute to the dedication of the brave emergency service workers who ran into danger.
“We have all been moved by the actions of ordinary people who opened their doors, cared for scared youngsters, provided transport to concert-goers, and are giving blood at donor banks to help those injured. This great city is today demonstrating to the world the true spirit of Manchester.”
Liberal Democrat leader Tim Farron, who had been due to campaign in Gibraltar, said: “This is a shocking and horrific attack targeting children and young people who were simply enjoying a concert.
“My deepest sympathies are with the victims, and with families who have lost loved ones, as well as those desperately waiting for news.
“I would like to pay tribute to the bravery and dedication of the emergency services.
“This is an attack on innocent people and the nation is united both in its grief and its determination to stand up to this deplorable attack.”