One in ten schools in Scotland are starting the school year still searching for key staff in teaching and classroom support roles.

Across the country, a total of 231 schools have an active advert for staff, with some schools needing multiple vacancies filled.

There are particularly acute staffing gaps in the north-east, Fife and Edinburgh, according to the research by the Scottish Conservatives, who branded the figures "unacceptable".

The Scottish Government conceded there were "challenges filling vacancies in some areas" but pointed out teacher numbers had increased by more than 500 on last year - the second consecutive annual increase.

There are four head teacher and deputy head roles still vacant in Aberdeen, Aberdeenshire and Angus, with more than 50 schools across the north-east posting staff adverts.

Four head or deputy head positions are also going spare in Edinburgh and 20 schools in the capital still require key workers.

In Fife, a dozen schools are short of staff, with a deputy head teacher being sought for one of them and five more searching for English teachers.

Only three schools in Glasgow are looking to fill vacancies, but two of those are looking for new head teachers.

It comes as the new school year gets under way, with Glasgow and Edinburgh pupils going back on Wednesday while pupils in Dundee returned the previous day.

In some areas, like Stirling and Aberdeen, pupils do not go back until next week.

A spokesman for the Scottish Conservatives said: "It's unacceptable that, just as schools are preparing to go back, hundreds are still advertising for staff.

"It will be extremely difficult for head teachers to get ready for the year ahead if they don't have the right people in place.

"For some schools it may only be one or two people, but for others it will be significantly more."

He added: "This is hardly going to reverse the fortunes of Scotland's schools as they slip down global league tables.

"The SNP is in sole charge of education, has been for more than a decade, and has to explain why it has allowed this chaotic situation to emerge."

A Scottish Government spokesman said: "We have invested £88m in 2017, resulting in 543 more teachers than last year - the second year in a row that numbers have increased - in response to the challenges filling vacancies in some areas.

"Our ambitious reform agenda is aimed at making teaching an attractive career choice with varied opportunities to develop.

"We have taken decisive action to recruit and retain teachers through our Teaching Makes People campaign and have created new routes into the profession.

"We have also made bursaries of £20,000 available for career changers to train in priority subjects."

Scotland currently has record numbers of post-probationer teachers who have secured permanent or temporary contracts, at 88%.

Additionally, 2864 newly-qualified probationer teachers started on the teacher induction scheme last August - 231 (9%) more than the year before.