Family members say Laura Macintyre and Eilidh MacLeod haven't been heard from since the explosion.
Labour Push For More Welfare Powers
Labour has said it will push for welfare provisions in the Scotland Bill to be strengthened to protect against "the worst of the Tories''.
Shadow Scottish secretary Ian Murray will table several amendments to give Holyrood greater power over benefits in the Bill, which will be debated in the House of Commons today.
The Bill is the first from the UK Government's legislative programme announced in the Queen's Speech to receive its second reading.
Scottish Secretary David Mundell, who will open the debate, said it reflected the Government's commitment to deliver on further devolution.
He said: "The fact the Scotland Bill is the first piece of legislation to be debated in this new session sends a clear and strong signal of our intent to get on with the business of delivering significant new powers for Scotland.''
Labour's proposed changes include a guarantee that the Scottish Parliament will have the final say on welfare rates as well as the "unrestricted'' power to create new devolved benefits.
The party wants the full devolution of housing benefit and for Holyrood to be given the power to top up benefits, including in reserved areas.
Labour is also calling for control over welfare to be further devolved to local communities, starting with the work programme.
Mr Murray, Labour's only Scottish MP, is expected to say: "More devolution can protect the most vulnerable in Scotland from the worst of the Tories.
"The major new powers coming to Scotland give us the chance to do things differently, so that never again can a right-wing government impose the bedroom tax on struggling families.
"The final say on benefits paid in Scotland should be made in Scotland. The UK-wide welfare state should act as a minimum level of protection that we can top-up from our own resources if that's what Scots want.''
SNP MPs have said they will push for more powers over taxation, welfare, job creation and wages as the legislation makes its way through Westminster.
A party amendment says the Bill fails to fully implement the recommendations of the cross-party Smith Commission, set up after last year's referendum on independence to agree a package of further devolution for Scotland.
It points to the conclusion of the Scottish Parliament's Devolution Committee that the legislation does not meet ''the spirit or the substance'' of those recommendations, a claim disputed by the UK Government, which insists it is delivering on the promise for further devolution in full.
The SNP also argues that its landslide victory north of the border in May reflects a desire in Scotland for the proposals to be strengthened.
Mr Murray will say he accepts that the Bill is not perfect but will challenge the SNP to put the powers it will bring to good use.
He is expected to say: "When this Bill is passed and these new powers make their way to the Scottish Parliament, we look forward to the debate moving on to how the powers will be used rather than where they will sit.
"Labour has been very clear that we will use the new tax powers to invest £125 million in Scotland's schools.
"We will increase the top rate of tax to 50p for those earning more than £150,000 a year so that we can give young Scots a better chance in life.
"It's time for the SNP to say once and for all if they will do the same.''
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.
John Bermingham was also accused of assault and a breach of a Sexual Offences Prevention Order.
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