The phrase "a source of serious concern" is correct and usable in written English.
It can be used when discussing issues or situations that are troubling or alarming.
Example: "The recent rise in cyberattacks has become a source of serious concern for national security agencies."
Alternatives: "a matter of great concern" or "a significant worry".
"I guess when we're talking about how good friends treat one another, that's a source of serious concern as well".
"The view from the French is that Venezuela 'es en flames' and a source of serious concern for Cuba".
The performance of most African governments in implementing the reforms necessary to turn their economies around has also been a source of serious concern.
It was also a source of serious concern at the Italian Embassy in Cairo, which was preparing for the visit of a major business delegation, led by the Italian minister of economic development, Federica Guidi.
It is our view that the parliamentary action that essentially compels participation in the regulatory mechanism belies claims that it will be 'voluntary.' Indeed, it should be a source of serious concern to your government that autocratic leaders seeking to limit media freedom now cite the British example".
It was also revealed, at a sometimes bad tempered meeting of the Commons public accounts committee, that the Major Projects Authority still has UC graded as "amber-red", and is therefore a source of serious concern for the body responsible for overseeing the government's major capital programme.
Yugoslav military tactics also drove thousands of ethnic Albanian villagers from their homes, and by late summer the plight of these refugees had become a source of serious international concern.
A recent Conservative party report claimed that under President Xi "very serious threats to Hong Kong's freedoms have emerged as a source of grave concern".
Many of these were shown to be sources of serious concern in the qualitative research with many providers only moving on to talk about other aspects of their work and motivation once they had aired their grievances on these issues.
