The head of the engineering giant which has won a £65m contract at RAF Valley on Anglesey says he has no plans to "decimate the workforce."
Babcock will service Hawks at Valley's jet pilot training school
The 650 civilian workers employed by defence company Brown & Root and Marshall Aerospace - Brama - to carry out routine service work on Hawk jets learned on Thursday they had lost the contract to a rival, Babcock Defence Services.
They are now waiting to see how many people will be hired by Babcock, part of the Babcock International Group.
Peter Rogers, chief executive of Babcock, told BBC Radio Wales on Friday that he couldn't guarantee the safety of any jobs at the base.
But he added: "We have not taken this contract on the basis that we will decimate the workforce."
"These occasions are difficult for everybody involved and it produces a sense of uncertainty in the employees which I fully understand."
"We are delighted to get this and we can only make this work with the assistance and co-operation of the employees."
"What they can be sure of is, it's not our intention, and it never was our intention, to take this contract merely to reduce the numbers of employees in Anglesey."
'World class operation'
"It's a service and it's turning the operation, which has already made considerable progress, into a world class operation (of) which we can all be proud."
Alwyn Rowlands, regional organiser of Amicus, the union representing most of the workers, said there was nothing to suggest there would be any job losses.
In a separate development on Thursday, it was announced that Dara, which employs more than 2,000 people at St Athan in south Wales, had won a five-year contract to carry out overhaul work of Hawk jets.
But this would not affect the future of work at RAF Valley.
Brama said it was shocked by the Valley decision. A spokesman said that it would be an understatement to say the company was "disappointed".
Last year, Brama confirmed plans to create 100 jobs.
Brama took over the RAF Valley job from military personnel six years ago, and said it had built up a strong presence at the base.
RAF Valley officers have said that the work will remain at the base.
The transitional handover period will begin next month, with the new contract starting in April.
Babcock's £65m five-year contract, with options for a further three years, will involve
a full range of support services, from aircraft engineering to base support.