By David Deans
BBC Wales political reporter
Two schools on Anglesey have closed because of concerns over concrete, the Welsh government has said.
Pupils were meant to be returning to Ysgol David Hughes and Ysgol Uwchradd Caergybi on Tuesday.
They are the first schools to be identified by Cardiff ministers as having reinforced autoclaved aerated concrete (RAAC).
But work is continuing to assess the scale of the issue across Wales, with the results expected in two weeks.
The Health and Safety Executive has said that RAAC is now beyond its lifespan and may “collapse with little or no notice”.
Both schools are secondaries. Ysgol David Hughes is located in Menai Bridge, while Uwchradd Caergybi is in Holyhead.
It comes after RAAC was found in three Welsh hospitals earlier this year, with patients moved from one of them.
In a letter to parents, Ysgol David Hughes’ head teacher Emyr Williams said it was hoped the school would be partly or fully open by Thursday, while further safety inspections are carried out.
In announcing the closures, Education Minister Jeremy Miles claimed that evidence of incidents with RAAC that occurred over the summer were only provided to the Welsh government in writing at 18.57 BST on Sunday, “despite repeated requests”.
The incidents had led to there being a “heightened safety risk regarding the usage of RAAC”.
What is being done about RAAC in Wales?
Mr Miles’ statement says the Welsh government commissioned in May a “condition and energy survey of all state funded schools and colleges”.
“The nature of this survey would highlight any structures suspected of containing RAAC for further inspection.”
He added: “We are undertaking further work to verify the position across Wales and a review of the latest information held by local authorities is underway.
“We expect to have the results of that within the next two weeks.”
Once that is done Mr Miles said “we will engage with specialist structural engineers” to work with councils and colleges to undertake any urgent appraisal of newly identified instances as to the presence of RAAC.
“We anticipate completion of this work by the end of December,” he added.
He said the Welsh government has had an “extensive programme for the refurbishment and building of new schools and colleges” and has targeted £2.35bn towards new-build and major refurbishment projects.
Where else has RAAC been found in Wales?
Withybush Hospital, in Haverfordwest, Pembrokeshire, recently moved patients after the concrete was found there.
The material was also found in a “limited part” of Bronglais Hospital in Aberystwyth, Ceredigion.
At Nevill Hall Hospital, in Abergavenny, four offices, part of the restaurant and the chapel were closed earlier this month after RAAC was identified.
However, Aneurin Bevan University Health Board said the hospital was in a “different position” to Withybush and that no patient areas were affected.
The Welsh government has said RAAC does “not appear to be a widespread issue” in hospitals in Wales, and that all health boards have been asked to carry out survey work.
The UK government has been asked to comment on Mr Miles’ remarks.