Seventeen schools in Edinburgh remain closed for a second day due to building safety fears.
Around 7,000 primary and secondary school children are spending another day away from the classroom as inspections continue following the Easter break.
Urgent repairs are expected on four buildings after an external wall partially collapsed at a city primary during high winds earlier this year.
The schools were all built or refurbished under the same public private partnership (PPP) schemes around 10 years ago, leading to questions over the standard of construction and the use of such contracts generally.
Edinburgh City Council made the decision to shut 10 primaries, five secondaries and two additional support needs schools from Monday.
First Minister Nicola Sturgeon said: “These were schools built 10 or more years ago under a system of PFI that at the time people, including the SNP, had real concerns about – concerns being that these contacts prioritised private profit over quality and the interests of pupils.
“If it turns out that this is a legacy of those PFI projects, then there will be big questions for those who were in charge at the time to answer.”
Council officials said they aim to have all primary pupils back in the classroom by next Monday, while “significant work” has taken place to make sure the 2,000 S4, S5 and S6 pupils affected will be accommodated at high schools in the city.
Offers of support to accommodate pupils have come from organisations including Hibernian Football Club, the Scottish Parliament, Edinburgh University and NHS Lothian, as well as various community groups.
One of the schools under repair is Oxgangs Primary, which lost part of a wall during Storm Gertrude in January.
Closures were prompted across the school community after workers there found “further serious defects” with the building on Friday.
Construction group Galliford Try, which acquired responsibility for Oxgangs through its 2014 acquisition of Miller Construction, said it takes its role as contractor “very seriously”.
A company statement said: “In March this year we were notified that Oxgangs Primary School, built by Miller Construction more than 10 years ago, lost part of one external wall which blew off in Storm Gertrude.
“Oxgangs was built as part of Edinburgh’s PPP schools programme between 2002 and 2005.
“The programme, which comprised 17 schools in two phases, was managed by Edinburgh Schools Partnership. ESP subcontracted the construction of the schools to a number of contractors, including Miller Construction.
“Through its acquisition of Miller Construction, Galliford Try has contractual responsibility for four of the 17 schools.
“Remedial work required to remedy defects in those four schools is nearing completion and the costs are not material to the Group.
“Galliford Try takes its role as a responsible contractor very seriously and the safety of the pupils and staff is paramount.”
Parents have expressed concerns about senior pupils facing exams and frustration over having to arrange childcare at short notice.
Andrew Kerr, Edinburgh City Council chief executive, said: “We have plans in place to ensure all primary and special school pupils will be back in schools by Monday of next week, subject to the council getting access to the closed schools.
“Our focus is very much on getting our school children back into education as soon as possible. That remains our priority, particularly for those pupils preparing to sit their exams in May.”
Scotland’s largest teaching union, the Educational Institute of Scotland, has called for a review of all PPP contracts in Scotland and the Scottish Secondary Teachers’ Association has questioned “the cost to our children” of such deals.
A Government spokeswoman said: “The Scottish Government has offered its full support to City of Edinburgh Council to keep disruption to children’s education at an absolute minimum and has written to all local authorities to ask them to carry out any necessary checks on their own estate as soon as possible.”