The trade union representing workers at the Michelin tyre plant in Dundee said hope remains some jobs can be saved after the company announced plans to halt production within two years.
Michelin is understood to be the largest industrial employer in the city, with 845 members of staff.
The proposed closure has been described by Unite as a “hammer blow” for the city.
Talks will take place later on Tuesday between management and Economy Secretary Derek Mackay to discuss the future of the site.
Michelin said the market for premium smaller tyres such as those produced at the Tayside factory has dropped significantly due to an increase in cheap imports from Asia and a shift to larger car tyres.
The French firm said it was not economically viable to produce small, low-cost tyres at the Dundee site or switch to the production of larger tyres.
The site opened in 1971 is due to cease operations by mid-2020.
Unite regional officer Bob Macgregor said outside the plant: “We have to remain optimistic.
“We’ve got quite a long time before the plant closes to get a plan in place, to enact that plan, to try to secure at least some of the jobs for this plant.
“I met this morning with Derek Mackay and that was a positive meeting.
“He’s keen to work with the unions and the company to put a plan to Michelin that he thinks will be attractive to them to keep the plant in Dundee in some shape or form.”
Dundee East MSP Shona Robison said Michelin had appeared to have a “bright future” in the city after investing £61 million in the plant over recent years.
She told BBC Scotland: “Is there a viable plan that could save this plant? That’s the question that needs to be asked and needs to be looked at in detail.
“If the answer to that is Yes then it’s about looking at what would that take, where would it come from. Is there something within the Tay Cities Deal?
“I don’t know the answer to that, I think we’re all trying to digest the news at the moment, but my view is I certainly haven’t given up hope.”
The plant will remain closed following the announcement until 7am on Thursday to allow workers to digest the news.
Members of staff continued to leave and enter the base in Baldovie Road on Tuesday after a meeting with management.
The notice given to employees said the news “will have come as a shock to you and your families”/
It added: “It is very important to understand that these proposals have nothing to do with the factory’s performance.”
Michelin said it would provide a personalised support package for each worker, with the opportunity to train in new skills and the possibility of being redeployed within the company or elsewhere.
It will begin a consultation with employees and trade unions on the closure plan over the next fortnight.
Production for the next three years at the site was expected to stand at no more than 5.4 million tyres a year, described by the firm as “significantly below capacity”.
Unite Scottish Secretary Pat Rafferty said: “The workforce can be assured Unite will fight tooth and nail to save our factory, we will leave no stone unturned to keep this factory open.”