A steel company in Newport has gone into administration, the trades union, Community has confirmed.
A steel company employing more than 400 people has gone into administrative receivership.
Alphasteel, is thought to have at least 450 people working for it.
Trade union Community said the news about Alphasteel in Newport was "terrible" and "couldn't have come at a worse time," days before Christmas.
John Griffiths AM for Newport East said: "I understand it's in receivership. I was told this morning."
Politicians called it "devastating." The firm, which announced 80 job losses last month, has not commented so far.
The company was founded in 1974 but was taken over by Swiss-based Satico Ltd in 2003. More than 80 job losses were announced in November amid concerns about its future.
Michael Leahy, head of the union, said the company should be profitable and it should be able to find a buyer.
Mr Griffiths added: "We all knew they were in serious problems and that's been the case for some time."
The company was founded in 1974 and taken over by Swiss-based Satico Ltd in 2003.
He said he was liaising with Community and training agencies to help workers affected.
Mr Leahy said his union had "desperately tried to help the company out of the situation it has found itself in".
According to its website: "Alphasteel Ltd was established in 1974 with the aim of operating a 'mini mill' steel works producing an alternative supply of hot rolled sheets and coils for UK consumption."
The highly skilled, efficient and effective workforce deserve long-term security and we will do our utmost to ensure all avenues are explored to keep these vital jobs John Griffiths AM, Newport East
He said Community would work with the receiver, the Welsh Assembly Government and other bodies to try to find somebody to acquire the firm.
Mr Leahy said if there were redundancies the union would ask for help from the assembly government to provide counselling and support for workers and their families.
Newport East MP Jessica Morden said: "This is absolutely devastating for the hundreds of workers just before Christmas.
"I want to assure them that we will do everything we possibly can to work with the receivers, unions and Welsh Assembly Government to seek potential buyers".
Newport East AM John Griffiths said: "The highly skilled, efficient and effective workforce deserve long-term security and we will do our utmost to ensure all avenues are explored to keep these vital jobs".
'Important tradition'
Mr Griffiths said the "buoyant steel market" should make it possible to find a buyer.
"Steel is embedded in Newport, as well as our nation's history, and I hope that the 400-plus jobs, as well this important tradition, can soon be saved"
According to its website: "Alphasteel Ltd was established in 1974 with the aim of operating a 'mini-mill' steel works producing an alternative supply of hot rolled sheets and coils for UK consumption."
Phillip Price, correspondent for Metal Bulletin, an industry publication said: "The parent company of Alphasteel [Satico Ltd] was placed into administration in Switzerland, which is currently under appeal.
"Alphasteel had a petition to wind up the company filed against it and a court hearing has been scheduled for next year.
"What is clear is that Satico Ltd's future is in doubt and that of Alphasteel as well.
"We understand the Alphasteel plant was shut down after Satico Ltd went into receivership and isn't scheduled to open until January - the firm says it is shut for planned maintenance.
"It's very confusing, but very interesting that since Alphasteel was acquired by Satico it has had a number of problems - problems getting electricity, they've had to make redundancies."
He said the future for both firms was in doubt until matters were resolved for Satico Ltd.
Do you work at Alphasteel? Can you tell us anymore about what's happening or how it's affected you?
Do you work at Alphasteel? Can you tell us any more about what has happening or how it has affected you?
