Bombardier has refused to rule out job cuts in the UK as the aerospace firm announced plans to axe 5,000 roles.
The Canadian company said it is aiming to "streamline, lean out and simplify the company" as part of a restructuring initiative that aims to save 250 million Canadian dollars (£146 million).
Bombardier said the cuts will affect the global workforce but did not specify precisely where the axe would fall.
Around 4,000 people are employed at Bombardier's Belfast operation, with a quarter of those working on the Airbus A220 (C-Series) line.
When asked about the Belfast operations, a spokeswoman told the Press Association: "Following Bombardier's announcement today, we will take the necessary time to evaluate what this means for our aerostructures and engineering services business.
"We will communicate with our employees in more detail over the coming weeks."
The group also has operations in Derby, where it employs 1,600.
Unions reacted with fury to the news.
Michael Mulholland, GMB Regional Organsier, said: "GMB demands answers from Bombardier for our members in Northern Ireland.
"They have already suffered months of uncertainty following Trump's tariffs - now they are under the cosh again.
"Bombardier jobs are crucial to Belfast's economy and GMB will fight tooth and nail to save them."
The cuts will be made in the next 12 to 18 months and Bombardier will also sell off "non-core assets" worth about 900 million Canadian dollars (£524 million), including the Q Series aircraft programme and the de Havilland trademark.
Chief executive Alain Bellemare said: "We have set in motion the next round of actions necessary to unleash the full potential of the Bombardier portfolio."
Around 1,000 jobs were lost at the Belfast plant in 2016 as part of a global restructuring operation.
Another 375 redundancies were announced last year.
The shake-up comes after Bombardier recently warned stockpiling parts to mitigate the impact of a no-deal Brexit would cost the Belfast business up to £30 million.
Michael Ryan, the head of the firm's Northern Ireland operation, said spending such a sum to store goods is "not how we can afford to run a business" and is "cash that I don't have".
There are fears that the movement of goods could be disrupted by long queues at ports if the UK is unable to reach an agreement with the European Union over Brexit.