Johnston Press has announced plans to cut a "significant" number of journalists from its Scottish weekly titles, following a strategic review.
The publisher said it was changing its editorial structure to address challenges faced by the print industry.
It cited audiences migrating to digital platforms and "industry giants" like Google and Facebook changing the way people read their news.
Johnston Press did not say how many jobs could be lost.
But the National Union of Journalists (NUJ) said 25 posts were under threat at 24 out of 28 Scottish weekly titles.
In a statement, the Edinburgh-based publisher said: "The pace of change in the media industry is showing no signs of abating, as we continue to face the challenges posed by our audiences migrating to digital platforms, and industry giants like Google and Facebook changing the way people read their news.
"We have seen over the past year at least, a number of newspapers closing or being put up for sale as publishers struggle to confront the challenges."
It added: "This restructure is designed to ensure our news brands are able to continue to serve their communities - as their only source of trusted local news.
"However, it does mean that there will be a significant reduction in the number of editorial roles.
"We are working closely with the NUJ in Scotland, and will continue to do so, in order to ensure we can achieve the best outcome for affected staff within the new structure."
NUJ Scottish organiser Paul Holleran said: "Members were shocked at the scale of proposed job losses and are now aware of the long-term precarious position of 24 Johnston Press Scottish titles.
"So far the management team have worked closely with the union in providing relevant information, maximising consultation and responding positively to initial negotiations.
"We have been told that their plans will put these titles into profitability.
"From our point of view we want to save all the titles, protect the journalists who will continue to work on these papers and get the best possible deal for those members who choose to leave the business.
"They have agreed a sensible timeframe for consultation and negotiation and I am hopeful agreement can be reached as soon as is practicable."
According to the NUJ, the four titles which are not facing job cuts are the Falkirk Herald, Fife Free Press, Southern Reporter and Stornoway Gazette. The union added that they had been identified as "prime" titles which would be given extra support to target potential growth.