Nicola Sturgeon said the authorities cannot be sure there are no other Scots affected.
Family Appeal To 'Radicalised' Daughter
The parents of a "bedroom radical'' who travelled to Syria and married an Isis fighter have pleaded for her to return home.
Aqsa Mahmood, 20, left her Glasgow home in November after becoming radicalised, her family said.
Muzaffar and Khalida Mahmood said they were horrified that their "sweet, peaceful, intelligent'' child had joined jihadists in Syria.
They said in a statement: "We still love you, Aqsa, but we now have to put your family, your brother and sisters first as you have betrayed us, our community and the people of Scotland when you took this step.
"You have torn the heart out of our family and changed our lives forever. Please come home.''
They warned: "If our daughter, who had all the chances and freedom in life, could become a bedroom radical, then it is possible for this to happen to any family.''
Family members say Laura Macintyre and Eilidh MacLeod haven't been heard from since the explosion.
The families of two girls from the Western Isles missing after attending the concert in Manchester targeted in a terror attack have issued appeals on social media.
Crews were called to the former Royal Victoria Hospital site this afternoon.
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